.

Virginity Pledges as a Preventative Measures for Preventing Unwanted Sexual,

Behavioral, and Biological Outcomes:

A Systematic Review of Adolescents and Young Adults in the U.S.

Thesis

Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in

the College of Public Health of The Ohio State University

By

Nicole J. Murphy

College of Public Health

The Ohio State University

Thesis Committee

Maria Gallo, PhD, M.S., Advisor

Abigail Norris Turner, PhD

Copyrighted by

Nicole Murphy

2018

Abstract

A common approach of abstinence promotion is the virginity pledge, a promise to abstain from sexual intercourse. A systematic review was performed in order to assess existing literature pertaining to virginity pledges and their effectiveness among the American adolescent and young adult population. Twelve publications of cohort and cross-sectional designs met the criteria and were included in the qualitative analysis. While most studies support a statistically significant difference in sexual initiation or age of sexual debut between pledgers and non-pledgers, the pledgers that did participate in sexual relations had similar risk-taking behaviors to those that did not pledge. Religious commitment, high levels of morality, and highly supportive environments were often highly correlated to making a virginity pledge.

Keywords: Virginity pledge, abstinence pledge, abstinence-only, sexual initiation, oral sex, teenage sex, contraceptive use

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Acknowledgments

I would like to sincerely thank Dr. Maria Gallo and Dr. Abigail Norris-Turner for their ultimate patience and guidance.

iv

Vita

2010……………………….……..….. Winnacunnet High School, Hampton, NH

2014 …………………………………. B.S. Public Health, University of Massachusetts,

Amherst, MA

Fall 2014–Fall 2017…...... Student Research Assistant,

The Ohio State University, Columbus, OH

Presentations

Murphy, N., Gouin, S., Desai, D. (April 2014). Improving the Treatment of Malaria in

Sub-Saharan African Children by Increasing Education of Patent Medicine Vendors.

University of Massachusetts, Amherst Undergraduate Research Conference, Amherst,

MA.

Fields of Study: Public Health, Epidemiology, and Psychology

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Table of Contents

......

Abstract ...... iii

Acknowledgments ...... iv

Vita ...... v

List of Tables ...... vii

List of Figures ...... viii

Chapter 1. Introduction ...... 1

Chapter 2. Methods ...... 4

Chapter 3. Results ...... 7

Chapter 4. Discussion ...... 40

Bibliography ...... 46

Appendix A. Search Strategy ...... 50

Appendix B. Risk of Bias Assessment ...... 51

Appendix C. Evidence Table of included studies ...... 54

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List of Tables

Table 1 Study Summary……………...……………………...... ………………………...11

Table 2 Virginity Pledge and Sexual Intercourse ...... 25

Table 3 Virginity Pledge and Sexual Partners…………………………………………...28

Table 4 Virginity Pledge and Non-Coital Sexual Behavior ...... ……………………...32

Table 5 Virginity Pledge and Out-of-Wedlock Pregnancy ……………………………...39

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List of Figures

Figure 1 PRISMA Flow Diagram ...... 8

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Chapter 1. Introduction

The United States is unique in that a virginity pledge is a common approach to delay sexual debut (Landor & Simons, 2014). The idea of the virginity pledge program was formally introduced in 1993 in a Southern Baptist Church (Bearman & Bruckner, 2001;

Rosenbaum, 2006). This idea of a declaration of one’s abstinence from sexual intercourse until marriage spread across the country, and similar programs were created across America. Many pledge programs have been created since; True Love Waits and

The Silver Ring Thing being two of the most popular. In fact, True Love Waits claims to have had around 2.5 million pledgers since its inception in 1993 (“Baptist Press”, 2005).

These programs became increasingly popular in religious Christian settings, particularly

Southern Baptist or Evangelical denominations (Rosenbaum, 2006). Support for virginity pledges was often tangled with support for abstinence-only education, and religion and sexual education became seemingly intertwined.

These virginity pledge programs were designed to highlight the importance of purity and dedication to abstinence. Various organizations utilize information regarding virginity pledges to assess how effective an abstinence only sex-education program is. If many of the participants take a pledge of virginity, the program would be considered successful

(Rosenbaum, 2009). Success and effectiveness of pledge programs as a deterrent to intercourse can be evaluated by assessing sexual behavior and health outcomes among pledgers versus non-pledgers. In the United States, adolescents and young adults 15 to 24 years of age contribute about 9.7 million new cases of reportable STIs every year, nearly

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half of the total infections reported annually (HHS, CDC, & NCHHSTP, 2016). This is especially concerning, as this age group only comprises a quarter of the sexually active population (Boonstra, 2014; Wind, 2016). While teenage pregnancy rates have declined over the past decade, the United States still has one of the highest incidences of teen pregnancy among all developed countries (Sedgh, Finer, Bankole, Eilers, & Singh, 2015).

Around 6% of U.S. teenage females become pregnant every year (Boonstra, 2014).

1.1. The Virginity Pledge

The virginity pledge, also commonly known as an abstinence pledge or a purity pledge, is a promise to abstain from sexual intercourse (Bersamin, Walker, Waiters, Fisher, &

Grube, 2005). When someone traditionally thinks of a virginity pledge, they often imagine a public declaration of no sex until marriage, such as in a church group

(Rostosky, Regnerus, & Wright, 2003). The idea expands far beyond that. This particular public declaration is considered a “formal pledge of abstinence”; an individual can pledge until marriage or until he or she reaches an older age when they feel more mature. A private pledge differs, as the individual does not necessarily have to explicitly express their abstinence on a public level, but instead makes a personal, private commitment to remain a virgin (Bersamin et al., 2005). A person taking a pledge can consider themselves a private pledger, a public pledger, or both. Often, those who pledge publicly have also made an internal commitment to vow their abstinence from sexual intercourse.

In addition, a pledger can be considered an inconsistent pledger if they reported different pledge status, or more specifically retracted their pledge, at different points in

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longitudinal data collection (Hannah Brückner & Bearman, 2005a; Rosenbaum, 2006).

Studies found that this is common, as many pledgers retract their pledge status in later

Waves of data collection (Rosenbaum, 2006). By distinguishing inconsistent pledgers from consistent pledgers, this study aimed to capture how likely it is for pledgers to adhere to their word and abstain from sex (Hannah Brückner & Bearman, 2005a).

Adding to the complexity of understanding the different levels of commitment, a new

Wave of virginity pledgers consider themselves “born again virgins.” These were those who have already had sexual intercourse, but decide to further abstain from sexual intercourse until they were older or in a committed, long-term relationship (Rosenbaum,

2006, 2009).

1.3. Objective

The primary objective of this systematic review was to get a better understanding of the virginity pledge, especially its association with sexual behavior and health. This review also seeks to uncover bias and gaps in the literature. By collectively evaluating existing research, a more thorough understanding can be had of the effectiveness of the virginity pledge in delaying or preventing sexual intercourse, negative biological, and behavioral sexual health outcomes.

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Chapter 2. Methods

2.1. Search and Data Collection

A systematic review of literature pertaining to virginity pledges was performed according to the widely accepted guidelines from PRISMA (Moher et al., 2015). The search strategy was created according to Cochrane in consultation with a research librarian.

Three main concepts were created for this search: ‘Virginity pledge,’ ‘adolescents and young adults,’ and ‘sexual behavioral or biological outcomes.’ A list of keywords pertaining to our predictor and these outcomes was created based on preliminary literature searches, MeSH terms, and a synonym generator. Boolean operators were used to connect these concepts and keywords to create a comprehensive search strategy. The primary outcomes of interest were sexual initiation, number of sexual partners, pregnancy, STIs, non-coital behaviors, and contraceptive methods.

Four database sources were used for this review: PubMed MEDLINE, CINAHL,

SCOPUS, and Google Scholar. In addition, the Grey Literature Report was searched for unpublished abstracts or papers pertaining to abstinence pledges. The search strategy was designed to be broad and initially inclusive of all publication types. The search strategy for PubMed can be found in Appendix A. Search strategies for the other databases were slightly modified in order to fit the specifications of the database search. Once a search was conducted, a title and abstract screen was done to eliminate obviously unrelated results. After this initial screen, the remaining publications were scanned in their entirety.

The following inclusion and exclusion criteria were applied to the full-text screen: 4

Inclusion Criteria

1. Publication was primary or secondary report of data

2. Study took place in the United States of America

3. Paper was in English

4. Participants were considered adolescents or young adults

b. Adolescents: ages 13-18 years old

c. Young Adults: ages 19-24 years old

5. Virginity Pledge was included as exposure or predictor

6. At least one behavioral or biological outcome was reported

7. Any sexual orientation

Exclusion Criteria

1. Paper was a literature review, news article, or a secondary/tertiary literature source

2. Study took place outside the United States of America

3. Paper was not in English

4. Virginity Pledge was not included as exposure or predictor

5. No behavioral or biological outcome was reported

6. None of the participants were ages 13-24 years old

Publications remaining after this step had full reference scans in order to identify any other possible sources missed by the database search.

2.2. Assessment of Quality

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Study quality and bias was assessed according to The Risk Of Bias In Non-randomized

Studies – of Interventions (ROBINS-I), an established bias measurement tool utilized supported by Cochrane (Sterne et al., 2016). This popular tool allows for a bias risk assessment of non-randomized studies in systematic reviews. Assessments of quality, as well as information regarding this tool, can be found in Appendix B. Study summaries with included strengths and weaknesses can be found in Appendix C. Please contact the author for individual publication assessments using the ROBINS-I tool.

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Chapter 3. Results

3.1. Findings

The search strategy identified 1,243 records through database searching and 727 through other sources; a total of 1,291 records, excluding duplicates (see Figure 1). Publications that were obviously not relevant to the topic were removed during the title and abstract screen. Once the 920 records were removed, a total of 371 full-text articles were further assessed for eligibility. After applying the inclusion and exclusion criteria, most of the articles were excluded for not having a virginity pledge predictor or exposure in their analysis. Many of the studies eliminated in this step pertained to abstinence-only education, and were deemed inappropriate to be included in an abstinence pledge systematic review. Twelve publications were obtained from this search strategy. The included studies and their descriptions were reported in Appendix C. The flow of information throughout the search strategy was outlined according to the PRISMA flow chart guidelines in Figure 1 (PRISMA, 2009). Search strategies and results for each database are available upon request.

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Figure 1.: PRISMA Flow Diagram

All twelve of these publications contained a virginity pledge variable, as well as at least one biological or behavioral outcome. Eight of these studies used data obtained from the

National Longitudinal Study of Adolescent to Adult Health, a nationally representative longitudinal survey of United States adolescents’. The other four results had populations varied in location, age, gender, orientation, and several other demographics. Almost all of

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these publications were of longitudinal design in a prospective cohort study. One study obtained its data through a cross-sectional design.

Often, those conducting a systematic review would combine data from separate studies to conduct both a qualitative analysis and quantitative meta-analysis. It was determined that the heterogeneity of measures, populations, and analyses made it impractical pool measures and outcomes and conduct a quantitative meta-analysis. A qualitative approach to analyzing these data would be to assess the overall effectiveness of virginity pledges, identify major bias in existing studies, and find major gaps in research.

The National Longitudinal Study of Adolescent to Adult Health (Add Health Study), previously the National Longitudinal Study of Adolescent Health, was a national surveillance effort of health habits and other behaviors of interest (Harris & Udry, 2008).

Among many variables included in the dataset, virginity pledge status, sexual health, and sexual behavior data were collected. Over 90,000, seventh through twelfth grade students were surveyed, making the Add Health Study the largest collection of data regarding adolescent sexual health. The Add Health Study began data collection in the 1994-1995 school year and since has had three more Waves of collection in 1996, 2001-02, and 2008

(Harris & Udry, 2008).

There were several publications pertaining to virginity pledges that utilize the data from the Add Health Study (Bearman & Bruckner, 2001; H Brückner & Bearman, 2004;

Hannah Brückner & Bearman, 2005a; Ford et al., 2005; Kirk A; Johnson & Rector, 2004;

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Manlove, Ryan, & Franzetta, 2003; Paik, Sanchagrin, & Heimer, 2017; Rector &

Johnson, 2005; Rosenbaum, 2006, 2009; Rostosky et al., 2003). Each study provides certain insights into the virginity pledge and its association with a variety of behavior and health outcomes.

3.1.1. Study Quality and Risk of Bias

The ROBINS-I tool was used to assess the objective of studies, as well as their risk of bias. Descriptions of the studies for this purpose can be found below, in Table X. The risk of bias assessment using the detailed ROBINS-I tool can be found in Appendix B.

Overall, there was a moderate to serious risk of bias among the studies. A few studies had low to moderate risk of overall bias, often because the study had done extensive work to include confounders and adjustments. One large issue in this review, and within many of the individual publications, was that many outcomes were reported only among a select group of participants. For example, in a couple studies, oral sex was only measured among those who had not yet initiated sexual intercourse. In addition, condom use, sexual partners, and pregnancy were only really measured among those pledged virgins who have had intercourse.

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Table 1. Protocol and PICO for ROBINS-I Summary Protocol/ Name of Considered Study Design Participants Intervention Comparisons Outcomes Confounders Sexual No virginity pledge, intercourse private pledge, initiation; Any Baseline pledge until married, sexual health, characteristics, Including pledge until older, behavioral, religiosity, moral Review Systematic ages 13-24 Virginity Pledge inconsistent virginity biological values, social Protocol Review y/o (formal/public) pledge outcome. support Female adolescents Sexual Bearman (Grades 7 intercourse Gender, race, et al., Prospective through 12 Virginity Pledge initiation, condom social 2001 Cohort in 1995) (formal/public) No virginity pledge use environment Gender, age, race, expectations, Female and No virginity pledge, scholastic male private virginity achievement, Bersamin adolescents pledge-until married, Sexual religiosity, et al., Prospective (12-16 y/o Virginity Pledge private, virginity intercourse perceived peer 2005 Cohort in 1995) (formal/public) pledge-until older initiation, oral sex behavior, social 11

environment, parental attitude, social support. Gender, race, religiosity, ethnicity, social Female and Sexual environment, male intercourse attitudes about adolescents initiation, condom sex and Bruckner (Grades 7 No virginity pledge, use, STD/STI consequences et al., Prospective through 12 Virginity Pledge inconsistent virginity presence, HPV /experiences 2005 Cohort in 1995) (formal/public) pledge presence with sex. Gender, race, religiosity, ethnicity, social environment, Female and peer and parental male attitudes about adolescents sex and (Grades 7 consequences Ford et Prospective through 12 Virginity Pledge STD/STI /experiences al., 2005 Cohort in 1995) (formal/public) No virginity pledge presence with sex. Female Gender, age, adolescents race, religiosity, Johnson and young family et al., Prospective adults Virginity Pledge Pregnancy (out- background, 2004 Cohort (Grades 7 (formal/public) No virginity pledge of-wedlock) income 12

through 12 in 1995)

18-24 y/o Religious female and commitment, male religious college participation, students at Sexual age, gender a large intercourse public initiation, number southeaster of sexual Landor et Cross- n state Virginity Pledge partners, number al., 2014 Sectional university (formal/public) No virginity pledge of oral partners Female and Gender, male race/ethnicity, adolescents attitudes about (Grades 7 sex and through 12 consequences, in 1995) experiences with who had sex. first sex Sexual Manlove between intercourse et al., Prospective Waves 1 Virginity Pledge initiation, 2003 Cohort and 2 (formal/public) No virginity pledge contraceptive use

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Pre-pledge characteristics, gender, race/ethnicity Sexual religiosity, 12-17 y/o intercourse attitudes and Martino male and initiation, condom knowledge about et al., Prospective female Virginity Pledge use, non-coital sex and 2008 Cohort adolescents (formal/public) No virginity pledge sexual behavior consequences Gender, race, social environment, Female religiosity, adolescents perceived peer and young behavior, social adults environment, (Grades 7 Out of wedlock parental attitude, Paik et Prospective through 12 Virginity Pledge births, HPV social support, al., 2017 Cohort in 1995) (formal/public) No virginity pledge presence scholastic ability Sexual Matching on pre- intercourse pledge factors. Female and initiation, Gender, male contraceptive use, race/ethnicity adolescents oral sex, anal sex, religiosity, Rosenbau (Grades 7 number of sexual attitudes about m et al., Prospective through 12 Virginity Pledge partners, sex and related 2009 Cohort in 1995) (formal/public) No virginity pledge STD/STI consequences, 14

presence sexual knowledge

15-21 y/o Female and male Rostosky adolescents Sexual et al., Prospective /young Virginity Pledge intercourse Sex attitudes and 2003 Cohort adults (formal/public) No virginity pledge initiation beliefs, race 18-20 y/o male college students at a large, Sexual public, intercourse Age, race, high Williams southeaster No virginity pledge, initiation, condom risk drinking, et al., Prospective n Virginity Pledge private virginity use, number of impulsivity, 2013 Cohort university (formal/public) pledge sexual partners religiosity

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3.2. Virginity Pledge Prevalence

Most of the studies included in this review had virginity pledge percentages that were consistent with present understanding of virginity pledge prevalence (15-25%) (Bearman

& Bruckner, 2001; Bersamin et al., 2005; Hannah Brückner & Bearman, 2005a; Ford et al., 2005; Kirk A Johnson & Rector, 2004; Landor & Simons, 2014; Manlove et al.,

2003; Martino, Elliott, Collins, Kanouse, & Berry, 2008; Paik et al., 2017; Rosenbaum,

2009, 2006; Rostosky et al., 2003; Williams & Thompson, 2013). Table 1 describes the percentage of pledgers in each study, including public (or formal), private, or delayed

(“wait until older”, instead of married) pledge. Detailed information regarding these studies and their population characteristics can be found in Appendix C.

3.3. Outcomes of Interest

3.3.1. Virginity Pledge and Intercourse Initiation

Twelve publications gave information about virginity pledges and intercourse initiation, eight coming from the Add Health Dataset. One study in California included 870 adolescents aged 12-16 years old at Wave 1 in 2002 (Bersamin et al., 2005). The cohort was randomly selected from a large sample and followed for five Waves over a span of three years, but only the first three Waves were reported in this analysis. This prospective cohort examined the effectiveness of both private pledges and public pledges on the delay of sexual debut (n=763). Those who reported sexual initiation at baseline were removed in order to establish temporality between pledge status and intercourse initiation. The fully adjusted model included demographic and psychosocial factors in order to control

16 for differences in pledgers versus non-pledgers. Covariates including age, gender, race, and religiosity were examined with perspectives on sexual experiences and perceived parental and peer attitude. Results indicate that making a ‘private pledge until one was older’ significantly reduced the odds of initiating sexual intercourse in the one-year span evaluated. Compared to those who made a private pledge to wait until they were older to have sex, non-pledgers were 2.5 times more likely to initiate sex that year (OR=0.43,

95% CI 0.23, 0.79) (Bersamin et al., 2005). On the other hand, making a ‘private pledge until marriage’ was not significantly associated with a delay in intercourse. Additionally, declaring a formal pledge or being surrounded by fellow pledgers also did not have a significant association with the initiation of sex (Bersamin et al., 2005).

A third study examined the longitudinal associations between pledge status and sexual intercourse among 795 college males enrolled from a large, public southern university

(Williams & Thompson, 2013). This cohort was followed throughout their 4 years of college, and surveyed at the conclusion of each year. Crude and adjusted models were evaluated and reported for the study in order to assess pledging as a predictor of abstinence. Similarly to the aforementioned California study, private and public pledges were separated in order to better evaluate impact. In the bivariate logistic regression, males who partook in a private pledge were significantly more likely to remain abstinent throughout their college career, compared to their non-pledge counterparts. Male private pledgers were thirty-three times more likely to remain abstinent by the end of year one, twenty-one times more likely to remain abstinent by the end of year two, fourteen times by the third year, and fifteen times more likely to not engage in sexual intercourse by the 17 end of their college career and study period. Those who made a public pledge were four times as likely to remain abstinent in their first three years of college, and two times their final year, than their non-pledge counterparts (Williams & Thompson, 2013).

A multivariate logistic regression analysis was done. The adjusted model included age, race, religiosity, high risk drinking, and an impulsivity questionnaire (Williams &

Thompson, 2013). By controlling for these demographics and non-sexual behaviors, the researchers were able to examine the true effectiveness of pledging. This attempts to recognize how successful the pledge program was if pledgers and non-pledgers had similar characteristics. Even after adjustment, a private pledge was still significantly associated with a longer adherence to abstinence. At the end of each of the four years, male private pledgers were 24 times, 12 times, and 8 times (for both third year and fourth year) more likely to abstain from sex than their non-pledging counterparts. Unlike results provided by the crude model, a public pledge was not significantly associated with a delay in sexual intercourse over the four years (Williams & Thompson, 2013).

A cross-sectional study of young non-married, heterosexual adults (18-24 years old) from a large, southeastern state university investigated the role of religiosity and its moderating effect on pledge success (Landor & Simons, 2014). Virginity status was measured at the same time as pledge status, meaning the temporal relationship between these two factors could not be established. Respondents were asked if they ever or never had sex, and were also asked if they had ever taken a virginity pledge (yes/no). Three different models were approached in order to investigate how religiosity and related factors, and their

18 interactions, changed the association between pledge status and virginity status. When controlling for family structure, ethnicity, parental warmth (scale was provided), and socioeconomic status, pledge status and commitment to religion were both significantly associated with a delay in sex. Those who signed a virginity pledge had a 45.8% decrease in odds of initiating sex, compared to non-pledgers. This was also true for following models including religion, gender, and pledge interactions; Model 2 had two level interactions while Model 3 had three-way interactions (ex. Pledge status X religious commitment X gender). Model 2 uncovered that pledge signing was much more effective when religiosity was included as a covariate in the model. Interactions with religious commitment were significant for both pledge signing and gender. Model 3 introduced the three-way interactions to see the impact of gender on religiosity and pledge status, but all were insignificant (Landor & Simons, 2014).

Researchers conducting a prospective cohort study of a national sample of 12-17 year olds aimed to uncover what made pledgers different from non-pledgers (Martino et al.,

2008). They approached the issue of differential pre-pledge characteristics through a diverse and representative sample, as well as propensity-score weighing. Telephone interviews were used to survey participants at baseline (2001), as well as one and three years later. Those who reported sexual initiation at baseline were removed in order to establish temporality. This study found that over the three years, pledging was negatively associated with intercourse initiation (n=1105) (Martino et al., 2008). Around forty-two percent (42.4%) of those who did not pledge, but were matched to pledgers, initiated

19 intercourse in the study period. Comparatively, only 33.6% of pledgers initiated intercourse in this time (Martino et al., 2008).

Eight articles used data from the Add Health Study to investigate pledge status, and its relationship with sexual initiation, among a nationally representative sample. One data analysis by Dr. Rosenbaum used a subsample of these data and took those who had reported virginity pledges and matched each with three non-pledgers using the nearest neighbor method. Further differences in the pledger and non-pledger subsamples were reduced with a propensity score with replacement method. Sexual behaviors were reported for Wave 3 of the Add Health Study, virginity pledge status was measured at

Wave 1. There was no significant difference in mean age of sexual course initiation for pledgers (n=289) compared to their matched non-pledgers (n=645) (mean difference: ∆=

-3.58 years, 95%CI -9.58, 2.43). This study additionally looked at the number of times having sex in the past year and the age of first sex. There was no significant difference in these means between pledgers and non-pledgers. The study also added another dimension to sexual activity by seeing if there was a difference in pledgers and non-pledgers in

“receiving” or “giving” anal sex. While a greater mean average of pledgers had given anal, compared to non-pledgers, this result was insignificant (mean difference: ∆= 1.73,

95%CI -1.31, 4.77). Pledgers were also not significantly different from non-pledgers when it came to receiving anal sex (mean difference: -1.27, 95% CI -5.41, 2.87)

(Rosenbaum 2009). In Rosenbaum’s analysis of the Add Health Study, none of the sexual initiation outcomes were significantly associated with pledge status.

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One analysis of the Add Health dataset examined the role of religiosity and sex attitudes in predicting coital debut. Data from the first two Waves of surveys were used to create a predictive model of sex attitudes and behaviors at Wave 1 (1995) on coital debut at Wave

2 (1996). Of the 3,291 participants, aged 15 to 21, 13% of the 1,799 males and 22% of the 1,892 females self-reported making a virginity pledge at Wave 1. A series of five hierarchal logistic regression models were used in order to evaluate the influence of different attitudes and level of religiosity. All models separated effect by gender, and pledge status was not introduced until model 4. The first model included demographic information covariates like age, race, and mother’s education, as well as number of romantic partners (0-4); this was considered the baseline model. The second model simply added religiosity to the baseline model to see the effect of religiosity itself on coital debut. In Model 3, sex attitudes were evaluated and added to the logistic regression. Participants answered a series of questions using a sliding scale of strongly agree (1) to strongly disagree (5) to gauge how the participant felt about sex and possible outcomes (Rostosky et al., 2003).

Pledge status was introduced in model 4, and interactions of religiosity and pledge with

“Black” race were added in model 5. The motive was to see if race, religiosity, and sexual attitude accounted for the difference in coital debut between Wave 1 and Wave 2 in those that take virginity pledges versus those that did not. Their analysis suggested that religiosity and pledging were moderately correlated (males: r=0.28, females: r=0.24), as were several of the measured sexual perspectives and attitudes with pledge status.

Pledging, controlling for religiosity and these measured sexual attitudes, did not provide 21 significant differences in sexual debut. In the best-fit model (model 5), there was no significant difference in likelihood of coital debut for female pledgers (OR=0.90, p>0.05) or for black female pledgers (OR=1.12, p>0.05), compared to non-pledgers, when controlling for all factors and interactions. There was no significant difference in likelihood of coital debut for male pledgers (OR=0.85, p>0.05), but the interaction term for black male pledgers suggests a significant difference in those that pledge and do not pledge, among black males (OR=3.90, p<0.05), when controlling for all factors and interactions. Their analysis suggested that religiosity and pledging were moderately correlated, as were several of the measured sexual perspectives and attitudes with pledge status. Pledging, controlling for religiosity and these measured sexual attitudes, did not provide significant differences in sexual debut (Rostosky et al., 2003).

Another article primarily focused on how factors from Wave 1 of the Add Health Study, like pledge status, influenced contraceptive use among those who initiated sex between

Wave 1 and Wave 2. While the main predictor in this study was contraceptive use, this study first presented the percentage distribution of those who had first intercourse in that one year of follow up, by pledge status, according to gender. There was no significant difference overall in intercourse initiation between pledgers and non-pledgers; 16.7%

(p>0.05) of those who initiated sex took a virginity pledge. When stratified by gender, female pledgers did not differ significantly from female non-pledgers. On the other hand, the same analysis of male respondents (n=419) suggested that there was a significant difference in percentage distribution of sexual debut in those who took a virginity pledge compared to those that did not (11.2%, p<0.01) (Manlove et al., 2003). 22

A different Add Health analysis by Bruckner et al. investigated the transition to first sex for pledgers, inconsistent pledgers, and non-pledgers. By distinguishing inconsistent pledgers from consistent pledgers, this study aimed to capture how likely it was for pledgers to adhere to their word and abstain from sex. The median age of first sex among consistent pledgers was 19 years, among inconsistent pledgers was 18 years, and among non-pledgers was 17 years. Results suggest that when a pledger was consistent, the median age of first sex was delayed by one or two years, depending on gender, when compared to inconsistent pledgers and non-pledgers (Hannah Brückner & Bearman,

2005b). This difference in delay was noteworthy from a public health perspective.

A longitudinal data analysis of the Add Health Study performed by Bearman et al. did a comprehensive investigation on what accounts for different sexual activity levels across the adolescent population (Bearman & Bruckner, 2001). Data were drawn from 6,676 participants of the Add Health Study, a representative sample of the U.S. population. The analysis of the transition to first intercourse contained many models, which can be further reviewed in the evidence table in the appendix of this paper (Appendix C). Previous analyses suggested that race and gender were large factors affecting transition to first intercourse, and can possibly interfere with the accuracy of a virginity pledge effect. To combat this, Bearman included gender direct effects, gender interactions, pledge interactions, and social interactions. Interactions included were either two-way interactions or three-way interactions (Bearman & Bruckner, 2001).

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Focusing on the social context and environmental impact on the success of a virginity pledge, Bearman investigated if being surrounded by fellow pledgers (or not), or having a

“socially closed” school (or not), altered the effectiveness of the pledge (Bearman &

Bruckner, 2001). Socially closed schools were defined as “schools where the overwhelming majority of adolescents’ friendships were within school.” How effective the pledge works on the individual can depend on the percent of the peers that were pledgers. In the crude model, there was no delay effect of pledging. The final models considered the previously mentioned environmental factors, and their interactions. In socially open schools, when there were a lot of other pledgers, pledging was more likely to delay intercourse. They found that virginity pledges only worked in community (high school) settings where pledgers comprise over thirty percent of the population. The opposite was true in a socially closed context; when there were a larger percentage of nonpledgers in the population, the pledgers were more likely to transition to sexual intercourse earlier on. Bearman’s analysis brings light to how social environments and constructs can impact decision-making, and that pledging’s effectiveness may depend on the context of the situation (Bearman & Bruckner, 2001).

The most recent analysis of Add Health data suggests that there was no statistical difference in sexual initiation among those who reported no sex before Wave 1 (Paik et al., 2017). Eighty-one percent of pledgers and 83% of non-pledgers had sexual intercourse by Wave 3 (p>0.05) (Paik et al., 2017).

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Table 2. Virginity Pledge and Sexual Intercourse Initiation Study and Estimates P-value Adjustments (of reported Participants estimate/model) Bearman et al., Baseline RR (White,Asian, Gender, race, social 2001 Hispanic) =0.66* p<0.05* environment 95%CI (0.52, 0.83) n=6,676 Baseline RR (Black) =1.04 p>0.05 95%CI (0.70, 1.07) Bersamin et al., OR(Public)=0.71 p>0.05 Gender, age, race, 2005 95%CI (0.24, 2.13) expectations, scholastic OR(Private-married)= 0.53 p>0.05 achievement, religiosity, n=763 95%CI (0.24,1.18) perceived peer behavior, OR(Private-Older) =0.43* p<0.01* social environment, 95%CI (0.23, 0.79) parental attitude, social support Bruckner et al., Median age of first Gender, race, religiosity, 2005 intercourse (years) ethnicity, social No Pledge, Inconsistent, environment, attitudes n=11,471 Consistent about sex and All: 17, 18, 19 consequences Female: 17,18,18 p≤.0.000* /experiences with sex Male: 17,18,20 Wald Test: χ2 female=189, χ2 male=140 Landor et al., OR=0.540* p≤.0.05* Religious commitment, 2014 religious participation, n=1,380 age, gender Manlove et al., Percent distribution of p>0.05 Gender, race/ethnicity, 2003 respondents who have had attitudes about sex and sex that took a virginity consequences, experiences n=1,027 pledge: 16.7% with sex Only among Percent distribution of those who have respondents who have had first sex between sex that did not take a Waves 1 and 2. virginity pledge: 83.3% Martino et al., OR=0.606* p=0.02* Pre-pledge characteristics, 2008 gender, race/ethnicity religiosity, attitudes about n=1,105 sex and consequences, sexual knowledge

25

Rosenbaum et Difference in means of p>0.05 Matching on pre-pledge al., 2009 pledgers and non-pledgers factors. Gender, Δ=-3.58 95%CI race/ethnicity, religiosity, n=934 (-9.58, 2.43) attitudes and knowledge about sex and related consequences Rostosky et al., AOR(Male)=0.85 p>0.05 Sex attitudes and beliefs, 2003 AOR(Female) =0.90 race

n=3,691 p>0.05 n=1799 males n=1892 females Williams et al., OR(Wave4public)=0.86 p>0.05 Age, race, high risk 2013 99.64%CI (0.32, 2.32) drinking, impulsivity, n=795, 100% AOR (Wave4private) p<0.0036* religiosity male =7.55*(3.54, 16.09) *statistically significant result

3.3.2. Virginity Pledge and Number of Sexual Partners

Four studies in this analysis considered the effect of virginity pledge status on the number of sexual partners that individual had. These data were only collected about those who had engaged in sexual activity. The study of college males used multiple linear regression to determine if pledge status and type were associated with the number of lifetime sexual partners (Williams & Thompson, 2013). The number of sexual partners was important in order to understand the extent of negative outcomes associated with sexual activity, especially STIs. The measure of effect was the difference in the mean number of sex partners of pledgers compared to non-pledgers. This regression analysis shows the difference in number of partners between pledge type and non-pledge. Among those who engaged in sexual intercourse, a private pledge was not an effective predictor of the number of sexual partners during the first two years of college ([year1] t(447)=-1.38,

26 p>0.05; [year2] t(423)=-1.81, p>.05), but was a significant predictor the final two years of the study ([year3] t(428)= -2.97, p=0.003, [year4] t(439)=-2.48, p=0.014). Males who had engaged in sexual intercourse and made a private pledge had, on average, 1.38 less partners than their non-pledge counterpart in year 3.among those who havConversely, a public pledge was not significantly associated with the number of lifetime sexual partners

([year1] t(447)=-1.65, [year2] t(423)=-1.41, [year3] t(428)=-1.07, [year4] t(439)=-1.35; p>.05) (Williams & Thompson, 2013).

The southeastern cross-sectional study examined the effect of pledge status, and religiosity, as it relates to the number of lifetime sexual partners (Landor & Simons,

2014). Three models were created to test for an association between pledge signing and number of partners. All regression models controlled for family structure, ethnicity, socioeconomic status, and parental warmth/support. The number of vaginal sex partners was measured categorically: 0 (no partners), 1 (one partner), 2 (two to four partners), 3

(five to nine partners), or 4 (ten or more partners). Pledging was significantly associated with a decreased number of sexual intercourse partners, controlling for family structure, ethnicity, socioeconomic status, and parental warmth/support (Model 1 β=-.07, p<0.05)

(Landor & Simons, 2014). Model 2 controlled for all covariates in Model 1, plus interactions of pledging with religious commitment, religious participation, and gender.

In Model 2, pledgers who were religiously committed were more likely to have fewer sexual partners than their religious, non-pledged counterparts, when religious commitment was above the mean (Model 2 β =-0.19, p<0.001; >0.16 standard deviations above mean) (Landor & Simons, 2014). Contrariwise, when religious commitment was 27 low (<-1.07 standard deviations below mean) pledgers actually had significantly more sexual partners than their non-pledge, but equally committed to religion counterparts.

Additionally, females in this category tended to have fewer sexual partners than their male counterparts. The religious commitment and pledge interaction was the only statistically significant association when controlling for other Model 2 covariates. Model

3 adds three-way interactions of pledge and gender with both religious commitment and religious participation to Model 2. Again, the religious commitment and pledge interaction was the only significant association when controlling for Model 3 covariates

(Landor & Simons, 2014).

The 2009 analysis by Rosenbaum of the Add Health data had multiple measures to explore the influence of pledge status on frequency of sex and the number of sex partners.

After accounting for pre-pledge differences, the amount of lifetime partners did not significantly differ between pledgers and their non-pledge counterparts, but the mean of the number of past year partners was -0.11 lower in pledgers than non-pledgers (95%CI -

0.19, -0.02) and this difference was statistically significant (Rosenbaum 2009).

Table 3. Virginity Pledge and Number of Sexual Partners Study and Estimates P-value Adjustments (of reported Participants estimate/model) Landor et al., Model 2 Regression Religious commitment, 2014 Analysis of Signing Public religious participation, Pledge and # Partners age, race, gender, n=** β =-0.19 p<0.001* religious and pledge interactions

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Rosenbaum et Difference in means of Matching on pre-pledge al., 2009 pledgers and non-pledgers factors. Gender, Δ=-0.31 p>0.05 race/ethnicity, religiosity, n=934 95%CI (-0.63, 0.02) attitudes and knowledge about sex and related consequences Williams et al., Regression Analysis of Age, race, high risk 2013 Pledge and # Partners drinking, impulsivity, n=439, 100% tWave4public(439)=-1.35 p<0.05* religiosity male tWave4private(439)=-2.38 p>0.05 *statistically significant result **unable to find in study

3.3.3. Virginity Pledge and Non-Coital Sexual behavior

Six studies investigated the relationship between pledge status and other non-coital behaviors. In the ‘Among the Willing’ study, levels of non-coital sexual behavior were measured among those who had not initiated sexual intercourse by Wave 3 (n=579)

(Martino et al., 2008). Non-coital behavior was initially measured on a scale of 0-4

(kissing to oral sex) at baseline and individuals were classified according to their highest level of non-coital behavior experienced. Genital play and oral sex were combined and compared with no sexual experience and just kissing to create a binary variable suitable for a logistic regression approach. Pledge status was unassociated with non-coital sexual behavior (OR=0.698, p=0.11) (Martino et al., 2008).

The prospective cohort study of northern and southern California adolescents also looked at oral sex as a sexual health outcome (n=735) (Bersamin et al., 2005). Oral sex activity was measured dichotomously by asking participants if they have ever given or received oral sex. Those who had not made this pledge were 2.5 times as likely to engage in oral sex then their private pledge (until older) counterparts (OR=0.41, 95%CI 0.24, 0.69, 29 p<0.05) (Bersamin et al., 2005). Those who took a private pledge to wait until marriage were also less likely to engage in oral sex in the year of follow up reported (OR=0.49,

95%CI 0.26, 0.95, p<0.05). Participating in a formal pledge was not significantly associated with a difference in engaging in oral sex by Wave 3 (Bersamin et al., 2005).

The southeastern cross-sectional study of college students also looked at oral sex as an outcome of interest (Landor & Simons, 2014). There were three hierarchal regression models; models 1, 2 (two-way interactions), and 3 (three-way interactions). Results suggest that religious commitment was a better indicator of oral sex participation in both pledgers and non-pledgers; the higher the religious commitment, the lower the amount of oral partners. In Model 2, the interaction of religious commitment with pledging was significant, but when this was combined with a gender interaction in Model 3, it became insignificant (Landor & Simons, 2014). Again, while pledgers have significantly fewer oral sex partners than their non-pledging matches, there was a crossover effect of religiosity, as seen in the number of sexual partners outcome. This suggests that those who were pledging have characteristics similar to those with high religiosity (Landor &

Simons, 2014).

The study of northern and southern California adolescents also looked at oral sex as a sexual health outcome (n=735). Oral sex activity was measured dichotomously by asking participants if they have ever had oral sex (given or received). This study found similar trends in oral sex and pledging as they did in vaginal sex for those who made a private pledge to wait to have sex until they were older. Those who had not made this pledge

30 were 2.5 times as likely to engage in oral sex then their private pledge (until older) counterparts (OR=0.41, 95%CI 0.24, 0.69). Those who took a private pledge to wait until marriage were also less likely to engage in oral sex in the year of follow up reported

(OR=0.49, 95%CI 0.26, 0.95). Participating in a formal pledge was not significantly associated with engaging in oral sex by Wave 3 (Bersamin et al., 2005)

The southeastern cross-sectional study of college students also looked at oral sex as an outcome of interest. There were three hierarchal regression models; models 1, 2 (two-way interactions), and 3 (three-way-interactions). Results suggest that religious commitment was a better indicator of oral sex participation in both pledgers and non-pledgers; the higher the religious commitment, the lower the amount of oral partners. In Model 2, the interaction of religious commitment with pledging was significant, but when this was combined with a gender interaction in Model 3, it became insignificant. Again, while pledgers have significantly fewer oral sex partners than their non-pledging matches, there was a crossover effect of religiosity, as seen in the number of sexual partners (Landor &

Simons, 2014). This suggests that those who were pledging have characteristics correlated to those with high religiosity.

Rosenbaum’s analysis of the Add Health Study measured if there was a significant difference in the prevalence of oral sex between pledgers and their matched non-pledgers.

Neither statistic proved a significant difference in both receiving oral and giving oral, as reported by Wave 3 of the Add Health Study (Difference in means of receiving oral:

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Δ=2.08, 95%CI -4.78, 8.94; Difference in means of giving oral comparing pledgers and non-pledgers: Δ=-0.46 95%CI -7.40, 6.48) (Rosenbaum, 2009).

Table 4. Virginity Pledge and Non-coital sexual behavior Study and Estimates P-value Adjustments (of reported Participants estimate/model) Bersamin et al., Oral Sex Gender, age, race, 2005 OR(Public)=0.78 p>0.05 expectations, scholastic 95%CI (0.35, 1.76) achievement, religiosity, n=763 OR(Private-married)=0.49* p<0.05* perceived peer behavior, 95%CI (0.26, 0.95) social environment, OR(Private-Older) =0.41* p<0.05* parental attitude, social 995%CI (0.24, 0.69) support. Landor et al., Oral Sex Religious commitment, 2014 OR=0.540* p≤.0.05* religious participation, age, gender n=1,380 Martino et al., Those who had engaged in Pre-pledge characteristics, 2008 non-coital behavior gender, race/ethnicity OR=0.698 p=0.11 religiosity, attitudes about n=579 among sex and consequences, those who had sexual knowledge not initiated sex Rosenbaum et Difference in means of Matching on pre-pledge al., 2009 receiving oral pledgers and factors. Gender, non-pledgers Δ=-2.08 race/ethnicity, religiosity, n=934 95%CI (-4.78, 8.94) p>0.05 attitudes and knowledge Difference in means of about sex and related giving oral pledgers and consequences non-pledgers Δ=-0.46 p>0.05 95%CI (-7.40, 6.48) *statistically significant result

3.3.4. Virginity Pledge and Contraceptive Use

In the ‘Among the Willing’ study, condom use was measured at Wave 3 for those who had reported sex in the past year (n=484) (Martino et al., 2008). Condom use was initially

32 measured as always, sometimes, and never, but was transformed to a dichotomous variable representing inconsistent condom use (always vs. sometimes/never). Pledge status was not significantly associated with condom use (Martino et al., 2008).

The study of male college students also provided insight on condom use at the end of years three and four (Williams & Thompson, 2013). There was only an adjusted effect measure, the adjusted odds ratio, reported for condom use in this study. The logistic regression model was adjusted for age, race, high-risk drinking, impulsivity, and religiosity. Among those who engaged in sexual intercourse, both public and private pledges were not significantly associated with condom use, controlling for age, race, religiosity, high-risk drinking, and impulsivity (Adjusted ORyear3=0.64, ORyear4 =0.85; p>0.05) (Williams & Thompson, 2013).

The analysis of the Add Health Study by Dr. Rosenbaum contained many approaches to measuring consistency and past history of condom use and birth control. This measure was restricted to those who reported sexual activity by Wave 3 and compared pledgers

(n=154) to matched non-pledgers (n=393). The mean difference for pledgers versus non- pledgers was used to identify significant covariates. In the past year, pledgers were

10.58% (95%CI -16.11, -5.05) less likely to always use a condom, 11.67% (95%CI -

17.64, -5.71) less likely to use a condom most of the time, 11.08% (95%CI -16.96, -5.20) less likely to use a condom half the time, and 8.58% (95%CI 3.62, 13.55) more likely to never use a condom, compared to their non-pledge counterparts. The same categorization method was used for birth control use in the past year. Pledgers were significantly less

33 likely to use birth control “always” (Δ=-5.97, 95%CI -11.93, -0.01) or “most of the time”

(Δ=-6.37, 95%CI -11.92, -0.82). They were also significantly less likely to use birth control “half of the time” (Δ=-6.36, 95%CI -11.59, -1.13) compared to non-pledgers. The measure of “never use birth control the past year had an insignificant mean difference between pledgers and non-pledgers. Additionally, Rosenbaum evaluated if they used birth control and condoms at their last sexual intercourse, and also asked if the individual had a condom break in the past year. Pledgers were statistically less likely to have used birth control at their last sexual encounter (Δ=-5.56, 95%CI -10.99, -0.12), but had no statistical difference when it came to last sex condom use and condom breakage (last sex:

Δ=-2.69, 95%CI -8.63, 3.26; breakage: 1.14 95%CI -3.55, 5.82) (Rosenbaum, 2009).

Another article investigated the patterns of contraceptive use among newly sexually active teenagers. Using data from the Add Health Study, Manlove et al., explored how pledge status at Wave 1 can influence contraceptive habits by Wave 2. In order to be considered in this analysis, respondents had to have self-reported sexual intercourse between Waves 1 and 2 of the study. Respondents were asked if they never, sometimes, or always used a contraceptive method during sex. Contraceptive methods included condoms and hormonal pills, and each subject could only be categorized into one contraceptive category. The contraceptive method reported in this analysis was whatever method the respondent deemed “primary.” Those who had taken a virginity pledge had significantly decreased odds of contraceptive use or consistency of contraceptive methods compared to those who had not taken a pledge (OR=0.43, p<0.05). In addition, those who reported taking a pledge in Wave 1 and had intercourse with someone they liked or were 34 in a romantic relationship with in the year of follow up were also less likely to always use contraception during those experiences (OR=0.54, p<0.1) (Manlove et al., 2003).

The analysis of Add Health by Bruckner et al. measured condom use at first sex across pledge groups (consistent, inconsistent, no pledge). Consistent pledgers and inconsistent pledgers were both significantly less likely to use a condom at first intercourse than their non-pledge counterparts. First intercourse behaviors, like condom and other contraceptive use, can be indicative of habits throughout the individual’s sexual life (Hannah Brückner

& Bearman, 2005b) The percentage of consistent pledgers that used condom at first sex

(54.6%) was significantly less then non-pledgers (59.7%); 54.9% of inconsistent pledgers used condoms (p<0.017) (Hannah Brückner & Bearman, 2005b) .

One study of Add Health Data by Bearman et al. considered contraceptive use as a whole. Contraceptive use for this analysis includes any protective measure, such as condom use and hormonal pills. A logistic regression model was performed to test the odds of contraceptive use at first intercourse between pledgers and non-pledgers who have had sex. Pledgers who have had sex were 35% less likely to use a condom compared to non-pledgers (OR=0.65, p<0.05) (Bearman & Bruckner, 2001).

Due to the complexity of summarizing the diverse results on contraceptive use among pledgers and non-pledgers, individual study information regarding this outcome and its association with the virginity pledge can be found in Appendix C.

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3.3.5. Virginity Pledges and Sexually Transmitted Diseases

Publications that derived data from the Add Health Study concluded that overall, there was no statistical difference in STI rates among those who pledged and those who had not pledged. In the analysis done by Rosenbaum of the Add Health Study, both chlamydia and trichomoniasis infections in Wave 3 were not significantly associated with pledge status in Wave 1 (Rosenbaum, 2009). Confidence intervals used to compare differences in mean prevalence of infections among pledgers versus non-pledgers cross the boundary of 0, indicating insignificance (Chlamydia: -1.83, 95%CI -4.26, 0.61;

Trichomoniasis -0.09, 95%CI -1.94, 1.76). Measures of Gonorrhea were not provided in results (Rosenbaum, 2009).

The Add Health analysis by Bruckner et al. uncovers the STD consequences that come from abstinence pledge programs. Overall, non-pledgers, inconsistent pledgers, and consistent pledgers did not show significant differences by group in self-reported STI history (p=0.475) (Hannah Brückner & Bearman, 2005b). There was a significant difference in percentage of pledgers and inconsistent pledgers versus non-pledgers when it came to rates of self-reported HPV among females (p=0.018). Nonpledgers had a higher rate of self-reported HPV (2.7%, 95%CI 2.1, 3.4) than consistent pledgers (1.1%

95%CI 0.4, 2.6) and inconsistent pledgers (1.4%, 95%CI 0.8, 2.6). Urine analysis tests in

Wave 3 gave a different prevalence of STIs among this population. There was a significant difference between pledgers and non-pledgers in females tested for trichomoniasis, chlamydia, and gonorrhea, as well as HPV; non-pledgers had higher STI

36 prevalence compared to pledgers (p<0.01). There was no significant difference among males (p= 0.145) (Hannah Brückner & Bearman, 2005b).

A study by Dr. Ford et al. analyzed how virginity pledge status at Wave 1 (1995) impacted the risk of sexually transmitted infections at Wave 3 (2001). Data were used to explore the possibility of a significant difference in STI prevalence in sexually active pledgers versus sexually active non-pledgers over the six years of follow up (Ford et al.,

2005). To assess how virginity pledge status at Wave 1 (1995) impacted the risk of sexually transmitted infections at Wave 3 (2001), a urine specimen analysis was done on

81% of Wave 3 participants (n=11,594). Results from these tests were used to explore the possibility of a significant difference in pledgers versus non-pledgers over the six years of follow up. The study found that there was no statistically significant difference between Wave 1 pledgers and non-pledgers and Wave 3 STI results (OR= 0.79, 95%CI

0.56, 1.11). This result remained insignificant even when stratified by gender (OR= 0.85,

95%CI 0.60, 1.19; Male OR=0.87, 95%CI 0.47, 1.59; Female OR=0.83, 95%CI 0.56,

1.22). Pledge status was unable to predict the risk of sexually transmitted infections by

Wave 3 (Ford et al. 2005). The study found that there was no statistically significant difference between Wave 1 pledgers and non-pledgers for Wave 3 STI results (Ford et al., 2005).

An analysis of human-papilloma-virus (HPV) analysis was done by Paik et al. using the

Add Health Dataset (Paik et al., 2017). It was important to note that HPV status was measured only among those participants who had engaged in sexual intercourse by Wave

37

3. There was no significant difference in the prevalence of HPV among pledgers when compared to non-pledgers (Paik et al., 2017).

Due to the complexity of summarizing the diverse results of STD/HPV information among pledgers and non-pledgers, individual study information regarding this outcome and its association with the virginity pledge can be found in Appendix C.

3.3.6. Virginity Pledge and Pregnancy

Two publications investigated the relationship between virginity pledges and pregnancy, specifically out-of-wedlock, or pre-marital, pregnancy. Both studies utilized Add Health

Study data to calculate the likelihood of an out-of-wedlock birth in pledgers versus non- pledgers. The 2004 paper by Johnson et al. used logistic regression modeling to estimate the odds of a pledger becoming pregnant by Wave 3 (2001) (Kirk A Johnson & Rector,

2004). Both consistent and inconsistent pledgers had statistically significant associations with out-of-wedlock births. Those who consistently pledged were 45.6% less likely to have a child born out of wedlock, compared to non-pledgers (OR=0.544, p=0.004). Those who inconsistently pledged were 23.3% less likely to have a child born out of wedlock, compared to non-pledgers (OR=0.757, p=0.048) (Kirk A Johnson & Rector, 2004).

A more recent analysis of Add Health data found that non-marital pregnancy was higher among non-pledgers compared to pledgers (Paik et al., 2017). A multinomial logistic regression of non-marital pregnancy identified pledging as a significant predictor of non- marital pregnancy (n=1,335). Pledging increased the risk of out-of-wedlock pregnancy by

51% (HR=1.51, p<0.05). A different analysis done by Paik et al. found around 20-25% of 38 the pre-marital pregnancies were planned in both pledgers and non-pledgers alike (Paik et al., 2017).

Table 5. Virginity Pledge and Pregnancy (Out-of-Wedlock) Study and Estimates P-value Adjustments (of reported Participants estimate/model) Paik et al., Risk of pre-marital pregnancy, Gender, race, social 2017 pledge vs. non-pledge environment, religiosity, HR=1.51* p<0.05* perceived peer behavior, n=1,335 social environment, parental attitude, social support, scholastic ability Johnson and Odds of pre-marital pregnancy, Gender, age, race, Rector, 2004 type of pledge vs. non-pledge religiosity, family OR(consistent)=0.544* p=0.004* background, income OR(inconsistent)=0.757* p=0.048*

*statistically significant result

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Chapter 4. Discussion

Twelve studies met the inclusion criteria and were included in the systematic review.

Generally, signing a virginity pledge was significantly associated with a decrease in the number of sexual partners when controlling for certain background variables, religiosity, and risk-taking behaviors. The collective results from the Add Health Study suggest that other factors may impact the effectiveness of the virginity pledge on postponing intercourse, and related behaviors (Harris & Udry, 2008).

While there was a significant difference overall, one study found that when religious commitment was low, pledgers actually had more sexual partners than their non-pledge counterpart. This suggests that religious commitment may be a large factor when determining the number of sex partners had.

Qualitative analysis of the data shows that there were mixed results when it came to pledge status predicting oral sex and other non-coital sexual behaviors. Those who made a private pledge, either to wait until older or when married, had a statistically significant decrease in odds of having oral sex when compared to non-pledge counterparts. On the other hand, the traditional formal pledge was not significantly associated with a delay in oral sex or other sexual touching. Results also show that religious commitment was again a factor in determining risk of oral sex or other non-coital touching.

Among those who had sexual intercourse, condom use was not statistically predicted by pledge status. Results show that there was equal inconsistent condom use among those

40 who had made any type of pledge, and those that did not pledge. According to a 2009

Rosenbaum publication, condom usage at first intercourse can reflect lifelong habits in sexual health (Rosenbaum, 2009).

There was a study of Add Health Data by Rector and Johnson regarding sexually transmitted diseases and their association with condom use and virginity pledges . This information provides insight into the condom habits at first intercourse, and overall, of those who get sexually transmitted diseases. It did not seem appropriate to include these results as it was about virginity pledges among those with STD positive status.

When the type of pledge was examined, there often was a difference seen in results of private pledgers versus formal/public pledgers, as with consistent versus inconsistent pledgers. Those who were private pledgers often had better successes at delaying intercourse than the public pledgers. Those who made public pledges did not have significantly different results than non-pledgers. It does make more sense that when someone makes a promise to himself or herself to abstain that they were doing it for personal reasons, whether those were due to religious, personal, or social influences. A public pledge could be done to please certain parents, peers, or groups, and perhaps these pledgers do not truly believe that they should wait, or even want to wait. Additionally, in studies where pledge status was broken down into “until marriage” or “until older,” only those pledging until older had a statistically significant decrease in delaying intercourse.

41

Collectively, the included studies suggest that while virginity pledges can be effective in delaying intercourse (and therefore the increased risk of negative health outcomes), it was generally only effective on populations that have characteristics highly associated with pledge taking. High religious commitment and traits that were deemed high in morality were very correlated, or accounted for most of the differences between pledgers and non- pledgers. Religious participation alone was not a factor in reducing sexual initiation, but when those who participate in religion were very committed to that religion, a delay in sexual intercourse among pledgers was noted. In addition, having a highly supportive environment was associated with a delay in pledging. For example, when a pledger was surrounded by other pledgers, they were less likely to engage in sex. These studies suggest that certain social environments can affect how an individual adheres to the pledge (Barnett, Martin, & Melugin, 2018; Bearman & Bruckner, 2001; Manning, 2017;

Rostosky et al., 2003). When these factors were controlled for, the statistical significance between pledgers and non-pledgers disappeared. Much of the research utilized in this review supports the fact that there were certain traits that were correlated with pledging.

The Coital Debut study, in particular, highlights this point as it reports high correlations of taking a virginity pledge with high reported religiosity, little perceived positive sexual outcomes, high perceived negative sexual outcomes, and parental and peer disapproval

(Rostosky et al., 2003).

Multiple longitudinal data analyses of cohort studies by Martino, Williams, and Landor attempted to fully understand how pledgers were different from non-pledgers. Propensity

42 score methods, multivariable logistic regression, and other methods were utilized to examine this difference. These statistical methods can have some downfalls when trying to apply conclusions to public health. By controlling for pre-pledge factors, these studies investigated if the pledge status still made a difference when the characteristics in the two populations were comparable. If these covariates were removed, the researchers were only looking at a very specific population that may not have results applicable to the general public.

In addition, a brief literature search provided publications suggesting many of those who pledged often withdrew their statement in later Waves of data collection (Barnett et al.,

2018; Kunz, 2015; Rosenbaum, 2009; Uecker, Angotti, & Regnerus, 2008). Rosenbaum hypothesized that a significant amount of those who reported taking a virginity pledge changed their status at some point in the survey. Fifty-three percent of those who reported pledging at Wave 1 denied pledging by Wave 2 (Rosenbaum, 2006). Five years after the

Wave 1 pledge, 82% of pledgers denied ever making a pledge. Pledgers who had initiated sex were over three times as likely to deny making a pledge than those who did not have sex. In addition, those who claimed making a pledge later in the study were more likely to retract their sexual histories. Rosenbaum concluded that the results presented in the

Add Health Study, or any related research, might not correctly represent true activity of pledgers (Rosenbaum, 2009).

Overall, while virginity pledges may be effective tool in delaying intercourse, these analyses suggest that it was a generally a very specific group of people with unique

43 characteristics that delay sexual activity. Since there was little significant difference found with condom use, other contraceptive use, and prevalence of sexually transmitted diseases (from Add Health Study results), it was of great importance to offer additional services or education along with the virginity pledge. Those that actively participate in pledge programs need to be aware of the negative consequences regarding sexual activity, whether oral, anal, or vaginal intercourse, in order to best protect the population from a spread in disease or other related risks.

4.1. Limitations

Firstly, there were a small number of studies identified that could be included in the review. Obviously, it would be ideal to have a large pool of studies to choose from. In addition, a quantitative meta-analysis was not practical in this review. A meta-analysis would provide pooled, summary estimates of each sexual health behavioral or biological outcome. This review provided a general summary of existing data, but not measures of the combined data.

When dealing with sensitive subjects, like sexual health (especially among a young population), there can be bias in the responses. A participant’s desire to respond the way they think they should may impact the truthfulness of their answers (Rosenbaum, 2006).

Rosenbaum uncovered that a significant amount of those who reported taking a virginity pledge changed their answer at some point in the survey. Rosenbaum suggests that any

44 difference in outcome by pledge status would be removed if the respondents were not honest. She proposes that virginity pledges may not reduce the likelihood of engaging in sexual activity, but may instead influence how adolescents report their sexual activity.

There may be cultural differences between today’s teenager and the 1990s teenager that may provide different sexual habits. The baseline of Add Health Data was 1994, potentially limiting the applicability of data to today’s adolescent population. Without ethical boundaries, the ideal method to see how a pledge would work on a general population would be to conduct a randomized control study and assign pledge status to virgins. Unfortunately, there is little feasibility of assigning a virginity pledge status, but would help clarify differences between pledgers and non-pledgers when it comes to pre- pledge characteristics.

4.2. Conclusion

Overall, virginity pledges were associated with a significant decrease in sexual initiation and the number of sexual partners, but were not significantly associated with reduced participation in oral, non-coital sex, or consistent condom usage. The characteristics of the traditional “private pledger,” one with especially high religious commitment, may account for the differences in pledgers and non-pledgers.

45

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Appendix

Appendix A. PubMed Search Strategy (((((((((((((((sexual abstinence[MeSH Terms]) OR sexual* AND abstinen*[Text Word]) OR sex abstinence[Text Word]) OR sex promise*[Text Word]) OR sex pledg*[Text Word]) OR abstinence pledg*[Text Word]) OR virginity pledg*[Text Word]) OR purity pledg*[Text Word]) OR celibacy[Text Word] OR pledge signer[Text Word]) OR pledge abstinence[Text Word]) OR pledge virginity[Text Word])) AND English[lang])) AND (((((((((((((adolescent[MeSH Terms]) AND young adult[MeSH Terms]) OR adolescen*[Text Word]) OR young adult*[Text Word]) OR teen*[Text Word]) OR preteen*[Text Word]) OR student*[Text Word]) OR school*[Text Word]) OR college[Text Word]) OR universit*[Text Word]) OR emerging adolescen*[Text Word]) OR emerging adult*[Text Word]) AND English[lang])) AND ((((((((((((((((((((((((((((sexual behavior[MeSH Terms]) OR sexual partner[MeSH Terms]) OR sex[MeSH Terms]) OR sexual health[MeSH Terms]) OR reproductive health[MeSH Terms]) OR reproductive behavior[MeSH Terms]) OR unsafe sex[MeSH Terms]) OR safe sex[MeSH Terms]) OR contraception[MeSH Terms]) OR condom[MeSH Terms]) OR coitus[MeSH Terms]) OR "pregnancy in adolescence"[MeSH Terms]) OR "sexually transmitted diseases"[MeSH Terms]) OR "pregnancy"[MeSH Terms]) OR "gonorrhea"[MeSH Terms]) OR "chlamydia"[MeSH Terms]) OR "trichomonas infections"[MeSH Terms]) OR "hiv"[MeSH Terms]) OR "acquired immunodeficiency syndrome"[MeSH Terms]) OR "condylomata acuminata"[MeSH Terms]) OR "granuloma inguinale"[MeSH Terms]) OR "syphilis"[MeSH Terms]) OR "herpes genitalis"[MeSH Terms]) OR "sexually transmitted diseases"[MeSH Terms]) OR sex[Text Word]) OR sexual health[Text Word]) OR reproductive health[Text Word]) OR sexual initiation[Text Word]) OR sexual behavior*[Text Word]) OR sexual partner*[Text Word]) OR sexual activit*[Text Word]) OR celibate[Text Word]) OR celibacy[Text Word]) OR coitus[Text Word]) OR coital debut[Text Word]) OR coital*[Text Word]) OR virgin*[Text Word]) OR abstinen*[Text Word]) OR first sex[Text Word]) OR first time[Text Word]) OR safe sex[Text Word]) OR protected sex[Text Word]) OR responsible sex[Text Word]) OR unsafe sex[Text Word]) OR risk behavior*[Text Word]) OR high risk[Text Word]) OR sexual intercourse[Text Word]) OR contraception[Text Word]) OR birth control[Text Word]) OR condom*[Text Word]) OR oral sex[Text Word]) OR anal sex[Text Word])) OR Gonorrhea[Text Word]) OR chlamydia[Text Word]) OR trichomoniasis[Text Word]) OR syphilis[Text Word]) OR HIV[Text Word]) OR HIV Infection*[Text Word]) OR Human Immunodeficiency Virus[Text Word]) OR AIDS[Text Word]) OR Acquired Immune Deficiency Syndrome[Text Word]) OR HPV[Text Word]) OR Human Papilloma Virus[Text Word]) OR Condylomata Acuminata[Text Word]) OR genital wart*[Text Word]) OR venereal wart*[Text Word]) OR pregnancy[Text Word]) OR pregnancies[Text Word]) OR gestation[Text Word]) OR sexually transmitted disease*[Text Word]) OR sexually transmitted infection*[Text Word]) OR STD[Text Word]) OR STDs[Text Word]) OR STI[Text Word]) OR STIs[Text Word]) OR Herpes[Text Word]) OR Herpes genitalia[Text Word]) OR venereal disease*[Text Word])) 50

Appendix B. Assessing risk of bias – ROBINS-I

Study Domain 1: Domain 2: Domain 3: Domain 4: Domain 5: Domain 6: Domain 7: ROBINS-I Confounding Selection Classification Deviation from Missing Measurement Selection overall of interventions data of outcomes of reported assessment Intervention results Low- Bearman Moderate et al., Risk of 2001 Moderate Moderate Moderate Moderate Low Low Low Bias Low- Bersamin Moderate et al., Risk of 2005 Moderate Moderate Low Moderate Moderate Low Low Bias Bruckner Moderate et al., Risk of 2005 Serious Moderate Low Moderate Moderate Low Low Bias Moderate- Serious Ford et al., Risk of 2005 Serious Serious Moderate Moderate Serious Moderate Moderate Bias Serious Johnson et Risk of al.2004 Critical Serious Moderate Serious Serious Serious Serious Bias Moderate Landor et Risk of al., 2014 Serious Moderate Moderate Moderate Moderate Moderate Low Bias

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Manlove Moderate et al., Risk of 2003 Moderate Moderate Moderate Moderate Serious Low Moderate Bias Low- Moderate Martino et Risk of al., 2008 Moderate Low Low Moderate Moderate Low Moderate Bias Serious Paik et al., Risk of 2017 Critical Serious Moderate Moderate Serious Serious Moderate Bias Low- Rosenbau Moderate m et al., Risk of 2009 Moderate Moderate Low Moderate Moderate Low Low Bias Moderate- Rostosky Serious et al., Risk of 2003 Serious Serious Moderate Moderate Moderate Moderate Serious Bias Moderate- Williams Serious et al., Risk of 2013 Serious Serious Moderate Serious Moderate Moderate Moderate Bias Assessed according to ROBINS-I Risk of Bias Assessment; Risk of Bias (Lowest risk of bias to highest risk of bias): Low, Moderate, Serious, Critical

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Appendix C. Evidence Table of included studies

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Study Population Methods Results Characteristics Virginity n=1461 Longitudinal Data Collection Main Results: Effect of making virginity pledge at T1 on sexual outcomes at T3 Pledges National, United Participants recruited from Among the States purchased national list of Virginity Pledge Willing 12-17 Years old at households with high b SE p baseline probability of having a 12-17 Intercourse initiation -.50 .22 .02* Martino et Virgin at T1 year old N=1105 al. 47% Female Less than Consistent Condom Use -.40 .34 .25 2008 23.8% Pledge at Telephone Interviews T1 N=484 baseline (2001),T2(2002), T3(2004): Noncoital Sexual Behavior -.36 23 .11 68% White 73%(n=1154) retention N=579 14% African Prospective American Outcomes: sex initiation, *Statistically significant p value. Cohort 12% Hispanic condom use, noncoital sexual Refusal rate as behavior (including oral sex) baseline: 36% Attrition was higher Analysis: Multivariate logistic among all races for regression model predicting teens over 14 at virginity pledge at baseline. baseline, boys, and Propensity score, matching, those with educated weighting parents. Promising n=870 Longitudinal Data Collection Variables associated with sexual intercourse, oral sex, (genital play not associated with pledge): To Wait 10 counties in Data drawn from first 3 Waves Respondents who initiated behavior in 2003 northern, southern of 5 Wave study Bersamin et California Wave 1 (fall 2002) n=1105 B S.E. Wald OR 95% CI Corr. al. 2005 12-16 years old at Wave 2 (spring 2003) n=891 Private Pledge- Married baseline Wave 3 (fall 2003) n=870 Oral Sex -0.71 0.33 4.49 0.49* 0.26, 0.95 -0.31** 49.0% Male Sexual Intercourse -0.63 0.41 2.41 0.53 0.24, 1.18 -0.25** 70.0%White Outcomes: sex initiation, oral Private Pledge- Older Prospective 17% Public Pledge sex Oral Sex -0.90 0.27 11.21 0.41** 0.24, 0.69 -0.41** Cohort 74% Private Pledge Sexual Intercourse -0.85 0.31 7.46 0.43** 0.23, 0.79 -0.36** Analysis: Participants took Formal Pledge 75% Estimated CASI and mail surveys, Oral Sex -0.24 0.41 0.35 0.78 0.35, 1.76 -0.10** response rate alternated at 6 month intervals Sexual Intercourse -0.34 0.56 0.37 0.71 0.24, 2.13 -0.08* Logistic regression hierarchal analysis *p<.05; **p<.01; Oral sex(n=735), vaginal intercourse(n=763)

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Examining n= 795 Longitudinal Data Collection Regression Analysis of pledge status as predictors of abstinence, and as predictors of condom use the Large, public, Data collected from sample of and sexual partners among those who have had intercourse: Prospective southeastern 1472 men who enrolled as 1st Effects university year, full time students, Wave 1 Wave 2 Wave 3 Wave 4 18-20 years old at 2007. Private Williams et baseline Followed for 4 years (2008- Abstinence: 33.01**, 22.89**ł 20.89**, 11.91**ł 14.04**, 7.53**ł 15.34**, 7.55**ł al. 2011) #Sex Partners: t(447)= -1.38 t(423)= -1.81 t(428)= -2.97* t(439)= -2.38* 2013 100% Male (n=795) 4 Waves of year end data Condom use: - - 1.31ł 1.42ł 27.3% Private Pledge collection from half hour (n=217) survey on sexual health Public 11.9% Public Pledge Wave 1 (spring 2008) Abstinence: 3.80**, 2.06ł 3.88**, 1.82ł 3.89**, 2.06ł 2.40**, 0.86ł (n=94) Wave 2 (spring 2009) 82%* #Sex Partners: t(447)= -1.65 t(423)= -1.41 t(428)= -1.07 t(439)= -1.35 Prospective 70.0% No Pledge Wave 3 (spring 2010) 75%* Condom Use: - - 0.64ł 0.85 ł Cohort (n=556) Wave 4 (spring 2011) 72%* 9.1% Public and *Retention unrelated to COR, AORł; COR= crude OR, AORł = adjusted OR with age, race, high risk drinking, impulsivity, Private (n=72) demographics and religiosity; p<.05*, p<.0036** 2.8% Public, not private (n=22) Outcomes: sex initiation, 18.2%Private, not number of sex partners, public (n=144) condom use Analysis: Bivariate Logistic regression, Multivariate regression analysis, Bonferroni adjustment

Why n= 1380 Participants recruited from Regression models predicting virginity status, number of sex partners and number of oral partners, Virginity Large, public, family studies, consumer controlling for background variables: Pledges southeastern state economics, and sociology Model 1 Model 2 _ Model 3_ __ Succeed or university classes during 2008-2009 Fail 18 to 24 Years Old school year Virginity Status B OR B OR B OR Male (n=410) Survey with retrospective self Pledge signing -1.16 0.31** -0.58 0.56* -0.61 0.54* Landor et al. Female (n= 970) reports. Religious Commit X Pledge - - -0.87 0.42** -0.87 0.42** 2014 73%White Virginity Status: 0 never had Religious Particip. X Pledge - - -0.01 1.00 0.08 1.09 19% African sex, 1 else Pledge X Gender - - 0.15 1.16 0.65 1.91 American # Intercourse Partners/ # Oral RC X Pledge X Gender - - - - -0.09 0.91 4% Asian Partners: RP X Pledge X Gender - - - - -0.69 0.50 2% Hispanic 0(none), 1(one), 2(two-four), 2Log likelihood 978.811 959.609 958.413 27%Pledge 3(five-nine), 4(10 or more) #Intercourse partners B SE β B SE β B SE β 55

Only non married, Pledge signing -0.18 0.08 -0.07* -0.13 0.10 -0.05 -0.13 0.10 -0.05 heterosexual Outcomes: virginity status, Religious Commit X Pledge - - - -0.36 0.07 -0.19** -0.36 0.07 -0.19** Cross- participants number of sex partners, Religious Particip. X Pledge - - - 0.03 0.08 0.01 0.03 0.09 0.02 Sectional number of oral sex partners Pledge X Gender - - - -0.07 0.20 -0.01 -0.05 0.23 -0.01 RC X Pledge X Gender ------0.03 0.18 -0.01 Analysis: Hierarchical RP X Pledge X Gender ------0.02 0.24 0.00 regression analyses. Adj. R- Squared 0.182 0.208 0.207 All models control for family #Oral partners B SE β B SE β B SE β structure, ethnicity, SES, and Pledge signing -0.08 0.07 -0.03 0.02 0.09 0.01 0.00 0.09 0.00 parental warmth Religious Commit X Pledge - - - -0.39 0.06 -0.20** -0.39 0.07 -0.20** Model 2 includes 2-way Religious Particip. X Pledge - - - -0.09 0.08 -0.04 -0.06 0.08 -0.03 interactions of the controls Pledge X Gender - - - 0.09 0.19 0.01 0.20 0.22 0.03 and main effects. RC X Pledge X Gender ------0.04 0.17 0.01 Model 3 contains 3-way RP X Pledge X Gender ------0.22 0.23 -0.04 interactions Adj. R-Squared 0.281 0.309 0.308 **p<0.001; *p<0.05

Patient n=3440 Data is subsample of National Sexual Behavior and Birth Control Use for Pledgers and Matched Nonpledgers, Wave 3 Teenagers? National, United Longitudinal Study of Means(SE) States Adolescent Health. Pledge (n=289) Nonpledge (n=645) Dif. in Mean (95%CI) Rosenbaum >15 years old in 1995 Those who had reported taken Sexual Intercourse 72.66 (2.63) 76.24 (1.69) -3.58 (-9.58, 2.43) 2009 Had not had sex and virginity pledge (n=289) were Premarital Sex and unmarried 53.29 (2.94) 57.09 (1.96) -3.81 (-10.70, 3.09) not taken a virginity matched with nonpledgers # of times sex in past year 22.83 (0.80) 23.68 (0.55) -0.84 (-2.76, 1.07) pledge in 1995 (n=645) by using exact and Age first sex 21.23 (0.33) 20.73 (0.22) 0.49 (-0.28, 1.26 ) Prospective nearest-neighbor matching Lifetime partners 3.22 (0.14) 3.52 (0.09) -0.31 (-0.63, 0.02) Cohort n=289 Pledgers with propensity scores. Past Year partners 1.09 (0.03) 1.20 (0.02) -0.11 (-0.19, -0.02) n=3151 nonpledgers, Follow up: 3 Waves (1995, Receive Anal 9.00 (1.69) 10.27(1.20) -1.27 (-5.41, 2.87) Add Health reduced to 645 when 1996, 2001) Given Anal 6.23 (1.42) 4.50 (0.82) 1.73 (-1.31, 4.77) Data matched Measured sexual behavior and Receive Oral 59.17 (2.90) 57.09 (1.96) 2.08 (-4.78, 8.94) thoughts along with urine Given Oral 50.87 (2.95) 51.33 (1.97) -0.46 (-7.40, 6.48) tested in Wave 3 (2001) for Chlamydia 2.42 (0.84) 4.25 (0.74) -1.83 (-4.26, 0.61) chlamydia, gonorrhea, Trichomoniasis 2.04 (0.77) 2.13 (0.53) -0.09 (-1.94, 1.76) trichomoniasis Gonorrhea 0.00 0.00 0.00 Always use condom past year 23.91 (2.13) 34.49 (1.66) -10.58 (-16.11,-5.05) Outcomes: Sex initiation, Most of the time use condom 42.03 (2.46) 53.70 (1.75) -11.67 (-17.64,-5.71) information about past sex Half the time use condom 50.72 (2.49) 61.81 (1.70) -11.08 (-16.96,-5.20) partners, oral sex, anal sex, Never use condom, past year 28.26 (2.25) 19.68 (1.39) 8.58 (3.62, 13.55) condom behavior, birth Always use birth control 45.65 (2.48) 51.62 (1.72) -5.97 (-11.93, -0.01) 56

control habits, STD presence. Most of the time use BC 63.77 (2.40) 70.14 (1.58) -6.37 (-11.92, -0.82) Half the time use BC 69.57 (2.30) 75.93 (1.47) -6.36 (-11.59, -1.13) Analysis: 3:1 propensity score Never use BC, past year 15.22 (1.79) 14.12 (1.19) 1.10 (-3.10, 5.29) matching Last sex use BC 66.67 (2.35) 72.22 (1.54) -5.56 (-10.99, -0.12) Last sex use condom 52.17 (2.49) 54.86 (1.70) -2.69 (-8.63, 3.26) Past year had condom break 26.85 (1.96) 25.71 (1.34) 1.14 (-3.55, 5.82)

Coital n= 3691 Data is from first two Waves of Likelihood of coital debut at Wave 2 for males and females Debut: National, United National Longitudinal Survey Model* 4 5 Role of States of Adolescent Health Male (n=1799) Religiosity 15 to 21 years old Follow up: Wave 1(1995) and Pledge 0.86 0.85 in Add Males (n=1799): Wave 2 (1996) Black X Pledge - 3.90** health 13% Pledged Females (n=1892): Tested if Wave 1 adolescent Female (n=1892) Rostosky et 22% Pledged religiosity and sex attitudes Pledge 0.89 0.90 al., 2003 predicted coital debut at Wave Black X Pledge - 1.12 2 Prospective Outcome: Sex initiation *Model 1,2,3 no pledge status accounted for; **p <0.01 Cohort Analysis: Correlation Analyses After accounting for the effects of the sex attitudes and beliefs, having pledged to remain a virgin Add Health and hierarchal logistic until marriage had no significant effect. Data regression models for males Pledging has no effect beyond its association with being religious and anticipating negative and females separately emotional outcomes of engaging in sexual intercourse. Pledging beyond the religiosity and sex attitude variables, did not significantly contribute to the odds of coital debut, not its interaction between race with religiosity and pledging.

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Predicting n= 18924 Data is sample of National Ability of Individual Factors at Wave 1 to longitudinally predict STI at Wave 3 Adolescents’ National, United Longitudinal Study of Longitudina States Adolescent Health. % Positive for STI OR (95% CI) l Risk for Grades 7 through 12 Follow up: 3 Waves (1995, Unadjusted Adjusted STI 1996, 2001) Virginity Pledge Wave 2 (n=14322) Measured sexual behavior and No 6.4% Referent Referent Ford et al. Wave 3 (n=11594) STD status with urine tested Yes 5.1% 0.79 (0.56, 1.11) 0.85 (0.60, 1.19) 2005 in Wave 3 (2001) for Male 0.87 (0.47, 1.59) 50.8% Male chlamydia, gonorrhea, Female 0.83 (0.56, 1.22) Prospective 67.6% White trichomoniasis Cohort 12.8% Pledge Outcomes: STD presence Add Health Data Analysis: STATA used for logistic regression analysis

Patterns of n=1027 Data is from first two Waves of % Distribution of respondents of Add Health study who had first sex between Wave 1 and Wave 2 Contracepti National, United National Longitudinal Survey All (n=1027) Female (n=608) Male (n=419) ve Use States of Adolescent Health Took a Virginity Pledge Grades 7 through 12 Sample included adolescents Yes 16.7% 20.6% 11.2%** Manlove et 41.4% Male who participated in both No 83.3% 79.4% 88.8% al. 70.5%White Waves, had first sex between 2003 16.7% Pledge Wave 1 and Wave 2. % Distribution of adolescents by consistency of contraceptive use Follow up: Wave 1(1995) and Never Sometimes Always Total Prospective Participants had to be Wave 2 (1996) Took a Virginity Pledge* Cohort virgin at Wave 1, but Yes 24.7 23.7 51.6 100.0 sexually active by Outcomes: Sex initiation, No 20.3 14.0 65.7 100.0 Add Health Wave 2. contraceptive use habits. Data Odds ratio from logistic and multinomial logistic regression of the likelihood that teenagers ever and Analysis: Logistic and always used contraceptives in their first sexual relationship multinomial logistic regression analysis All Romantic/liked Ever Always Ever Always Took a Virginity Pledge 1.08 0.43* 1.11 0.54*** *p<0.05 **p<0.01 ***p<0.001 Adolescents that took a virginity pledge had decreased odds of contraceptive use or consistency.

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After the Wave 1 (n=20745) Data drawn from National Transition to first sex and health behavior by virginity pledge Promise Wave 3 (n=15170) Longitudinal Study of Nonpledgers Inconsistent pledgers Consistent pledgers Adolescent Health. Sex Bruckner et National, United Follow up: 3 Waves (1995, Median Kaplan All 17 18 19 al. States 1996, 2001) Meier estimate age Female 17 18 18 2005 Grades 7 through 12 First vaginal sex Male 17 18 20 Data drawn from In home interviews conducted Prospective ADD study, students in high school students that % 95%CI % 95%CI % 95%CI p≤ Cohort in grades 7-12 in are a representative sample of Self reported TR/CH/GC 3.6 3.0, 4.2 3.1 2.2, 4.3 2.8 1.7, 4.5 .475 1995 the United States about Self reported HPV 2.7 2.1, 3.4 1.4 0.8, 2.6 1.1 0.4, 2.6 .018 Add Health sensitive health-risk Tested (TR, CH, GC) Data behaviors, including sexual. Females 30.3 28.2, 32.5 23.8 19.9, 28.2 18.5 13.9, 24.1 .000 Used ACASI to reduce Males 10.0 8.8, 11.3 7.5 4.7, 11.6 5.6 2.6, 11.7 .145 response bias Tested (HPV) Follow up survey in 2001 All 14.9 13.6, 16.3 10.3 7.9, 13.2 7.8 5.8, 10.3 .000 w/urine sample tested for Reported sexual activity 16.6 15.1, 18.2 10.9 8.3, 14.1 10.9 8.1, 14.4 .002 STDs. Ever seen doctor for STD All 22.9 21.2, 24.7 14.6 11.9, 17.8 14.1 11.0, 17.8 .000 Outcomes: Sex initiation, Reported sexually activity 20.8 19.3, 22.3 15.1 12.9, 17.6 15.9 12.4, 20.2 .000 condom use, STD presence Used condom at first sex 59.7 58.0, 61.4 54.9 51.2, 58.2 54.6 48.5, 60.0 .017

Analysis: Survivor Functions Notes: STD and Condom Use among those who reported sexual activity in Wave 3 and prevalence rates for data that are weighted in Wave 3.

Promising n=6676 Data is sample of National Transition to first intercourse the Future Data drawn from Longitudinal Study of White, Asian, Hispanic (n=5679) Black (n=997) ADD study, students Adolescent Health. Baseline Model Relative Risk 95%CI Relative Risk 95%CI Bearman et in grades 7-12 in Follow up: 3 Waves (1995, Pledge .66* .52, .83 1.04 .70, 1.07 al. 2001 1995 1996, 2001) Model with gender interaction 45% Male Direct Effects .50* .31, .80 .77 .35, 1.73 15%Black In home interviews conducted Gender Interaction 1.37 .80, 2.35 1.42 .56, 3.59 Prospective 20%Pledge in high school students that Models with pledge interactions Cohort are a representative sample of Model 1 the United States. About Pledge .64* .51, .81 1.02 .69, 1.52 Add Health sensitive health-risk Model 2 Data behaviors, including sexual. Pledge 1.00 .59, 1.68 1.51 .57, 4.00 Used ACASI to reduce Pledge in Socially closed school .39* .17, .90 ł .21** .09, .51ł 59

response bias %Pledgers (same sex) 1.00 .99, 1.02 1.01 .98, 1.05 %Pledgers X closed school 1.00 .98, 1.02 .94** .88, 1.01 Outcomes: Sex initiation, Pledge X %pledgers .98** .96, .99 ł .98 .92 1.04 contraceptive use Pledge X %pledgers X closed school 1.05* 1.01, 1.10 1.10** 1.05, 1.16ł

Analysis: Period Specific Effects Early Middle Late Early Middle Late Linear and logistic regression Pledge 3.73 .65** 1.09 1.29 .69 .97 Uses period specific effects, Pledge in Socially closed school .12* .50 .37 as well as determinants of %Pledgers (same sex) .99 1.01 1.00 pledging to explore its %Pledgers X closed school .99 1.00 1.02 effectiveness programs used Pledge X %pledgers .92 .98 .98 Pledge X %pledgers X closed school 1.12* 1.05 1.04

Logistic Regression of Contraceptive Use at First Intercourse Odds Ratio 95% CI Pledge .65* .43, .99

*p<.05 (one-tailed test), **p<.05 (two-tailed test), 90% CI ł Broken 100% female Data is from first two Waves of Out-of-wedlock pregnancy (n=1,335) Promises National, United National Longitudinal Survey Predictor HR SE States of Adolescent Health Pledge 1.51* 0.25 Paik et al., Grades 7 through 12 Follow up: Wave 1(1995) and Black X Pledge - 1.12 2017 Data drawn from Wave 2 (1996) ADD study, students HPV (n=3.741) Prospective in grades 7-12 in Tested if Wave 1 adolescent Pledge 0.89 0.90 Cohort 1995 religiosity and sex attitudes Black X Pledge - 1.12 predicted coital debut at Wave Add Health 23% Pledgers 2 *p<0.05 **p<0.01 ***p<0.001 Data Pregnancy and HPV analysis among those Outcome: Sex initiation who have had sex by Analysis: Survival analysis of Wave 3. pregnancy

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Adolescents 100% female Data is from first two Waves of Likelihood of Out-of-Wedlock Birth by Wave 3 Who Take National, United National Longitudinal Survey Virginity States of Adolescent Health Variable OR Sig. Pledges Wave 1(1995), Wave 2 (1996) Consistent Pledge 0.544 0.004 ** Have Lower Inconsistent Virginity Pledge 0.757 0.048* Rates Out- of-Wedlock Outcome: Likelihood of Birth *Significant at 95% Confidence Level Birth (out-of-wedlock) ** Significant at 99% Confidence Level

Johnson et Analysis: Logistic regression to al., 2004 assess likelihood of Out-of- wedlock birth Prospective Cohort

Add Health Data

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Strengths and Weaknesses of individual studies Author, Year Quality (Reference) Virginity Pledges Among Strengths: the Willing Propensity Scores and Covariate Controls to make pledger and nonpledgers to account for preexisting characteristics. Martino et al. Counterfactual framework to define effects of making pledge. 2008 Weaknesses: Measured self-reported sexual behavior; could be underreported due to reluctance or shame of truth or past pledge status. Promising To Wait Strengths: Pledge status separated into private pledge until married and older, and formal pledge. Bersamin et al. 2005 Weaknesses: Only over a one year period. Examining the Strengths: Prospective Effects Multivariate analysis to see if pledge was predictor of outcomes, controlling for relevant covariates Differentiated subjects by private or public pledge status. Williams et al. Has COR and AOR 2013 Weaknesses: One university population, may not be generalizable. Only focuses on males. Why Virginity Pledges Succeed or Fail Strengths: Several models with interactions of main effects. Landor et al. Investigates how religion impacts pledging and sexual outcomes, including signing and adherence. 2014 Weaknesses: Not a longitudinal design, no temporal relationship Lack of generalizability (college students) Measure of religiosity limited.

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ADD HEALTH Strengths: Propensity Scores and Covariate Controls to make pledger and nonpledgers comparable and account for Patient Teenagers? preexisting characteristics. Different levels of condom and other contraceptive use

Rosenbaum Weaknesses: 2009 Only measures at Wave 3 ADD HEALTH

Coital Debut: Role of Strengths: Religiosity in Add health Separates by gender

Rostosky et al. Weaknesses: 2003 Only examines one year between measuring religiosity and attitudes and measuring sexual debut ADD HEALTH

Predicting Adolescents’ Strengths: Longitudinal Risk for STI Includes individual factors like perceived peer/parental thoughts, lifestyle factors, maturity level. Weaknesses: Ford et al. Doesn’t measure HPV like other studies that examine STD rates. Doesn’t consider Wave 2 2005 ADD HEALTH Strengths: Patterns of Contraceptive Considers relationship status and friend groups. Short time between Wave 1 and Wave 2 limits recall bias. Use Weaknesses: Manlove et al. Only measures Wave 1 and Wave 2 may not have enough time to observe actual effects. 2003 ADD HEALTH Strengths: After the Promise Stratifies by race and gender Stratifies by pledge status Bruckner et al. Measures inconsistent pledgers in addition to pledgers and nonpledgers

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2005 Weaknesses Only vaginal sex reported, a short-term evaluation, not sufficient to predict long impact of STD rates. ADD HEALTH Strengths: Includes period specific effects for pledge status Promising the Future Includes table with determinants of pledging Social Influences on Sexual Debut Bearman et al. 2001 Weaknesses Data doesn’t observe process of pledging in sample schools over time.

ADD HEALTH Strengths: Statistical analyses is thorough, HPV related to number of partners and pledging. Broken Promises Includes table with determinants of pledging Paik et al. 2017 Social Influences on Sexual Debut

Weaknesses Population is only among the pledgers who have sex or among those with pre-marital pregnancy. “Pregnancy” is determined by birth, so abortions and other incomplete pregnancies would not be included. ADD HEALTH Strengths: Analyses included multiple adjustments for self-esteem. Out –of-wedlock Weaknesses pregnancies Population is among those who have had sex, or have had pregnancy. “Pregnancy” is determined by birth, so abortions and other incomplete pregnancies would not be included. Johnson et al. 2004

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Appendix D: Add Health Study Permissions

This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due Ronald R. Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health website (http://www.cpc.unc.edu/addhealth). No direct support was received from grant P01-HD31921 for this analysis.

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