INFLUENCE OF FAMILY DISRUPTION/FATHER ABSENCE ON DAUGHTERS’ AGE AT MENARCHE: A GENETICALLY AND ENVIRONMENTALLY CONTROLLED SIBLING COMPARISON STUDY A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology by Jacqueline M. Tither Department of Psychology University of Canterbury 2013 Table of Contents Acknowledgements .......................................................................................................................... i Abstract ................................................................................................................................................ ii Chapter One: Introduction ........................................................................................................... 1 Adolescence versus puberty ................................................................................................... 2 Puberty ............................................................................................................................................ 4 Adrenarche ............................................................................................................................... 6 Gonadarche ............................................................................................................................... 7 Physical manifestations of puberty ...................................................................................... 8 Pubertal status versus pubertal timing ...................................................................... 11 Sex differences ...................................................................................................................... 11 Variation in pubertal timing ................................................................................................ 12 Measuring puberty .................................................................................................................. 16 Objective measures of pubertal development ......................................................... 16 Subjective measures of pubertal development ....................................................... 20 Implications of “off-time” pubertal timing ..................................................................... 21 Genetic and environmental influences on pubertal timing ..................................... 24 Genetic influences on variation in pubertal timing ................................................ 25 Environmental influences on variation in pubertal timing ................................ 27 Geographic factors .............................................................................................................. 29 Intrinsic factors unique to individuals ........................................................................ 30 Extrinsic factors shared by family members ............................................................ 31 Family variables associated with variation in pubertal timing ......................... 33 Competing explanations for the association between family disruption/father absence and daughters' pubertal timing.................................... 40 Explanation 1. Family disruption/father absence and related factors........... 40 Explanation 2. A family-wide environmental confound ...................................... 52 Explanation 3. A shared genetic confound. ............................................................... 52 Previous attempts to address potential confounds .................................................... 54 Children-of-Twins design ................................................................................................. 56 Limitations of the Children-of-Twins design ............................................................ 57 The current sibling comparison study ............................................................................. 58 Specific a priori predictions of the current study ................................................... 60 Advantages of the current study’s design .................................................................. 61 Dysfunctional paternal behaviour as a potential moderator ............................. 64 Life history theory as a metatheoretical framework ............................................. 65 Overview of the current study’s aims .............................................................................. 68 Chapter 2: Method ........................................................................................................................ 69 Participants ............................................................................................................................ 70 Procedure ............................................................................................................................... 72 Measures ................................................................................................................................. 77 Computation of paternal dysfunction. ........................................................................ 82 Chapter 3: Results ......................................................................................................................... 86 Tests of major hypotheses ............................................................................................... 86 Potential confounding effects of between-family differences ........................... 89 Chapter 4: Discussion .................................................................................................................. 93 A note on causal inference ............................................................................................... 96 An international adoption comparison ...................................................................... 97 Consideration of competing explanations ............................................................... 104 Metatheoretical considerations ................................................................................... 108 Limitations of the current study .................................................................................. 109 Implications of the current study’s findings ........................................................... 115 Conclusion ................................................................................................................................. 116 References ..................................................................................................................................... 118 Appendix A .................................................................................................................................... 145 Appendix B .................................................................................................................................... 146 Appendix C ..................................................................................................................................... 147 Appendix D .................................................................................................................................... 148 Appendix E..................................................................................................................................... 151 Appendix F ..................................................................................................................................... 152 Appendix G .................................................................................................................................... 154 Appendix H .................................................................................................................................... 156 Appendix I ...................................................................................................................................... 158 Appendix J ...................................................................................................................................... 159 Appendix K .................................................................................................................................... 161 Appendix L ..................................................................................................................................... 163 Appendix M ................................................................................................................................... 165 List of Figures Figure 1. Differences between sisters in age at menarche in biologically intact versus biologically disrupted families. Error bars indicate 90% confidence intervals. .......................................................................................................... 87 Figure 2. Differences between sisters in age at menarche as a function of paternal dysfunction in biologically disrupted families. Error bars indicate 95% confidence intervals. .............................................................................. 89 List of Tables Table 1. Demographic Comparisons in Biologically Disrupted and Biologically Intact Families: The Current Sibling Study versus the Christchurch Health and Development Study .......................................................... 75 Acknowledgements I want to first acknowledge my University of Canterbury supervisory team— Professor Brian Haig, Dr. Fran Vertue, and Dr. John Freeman-Moir—for their collective wisdom, support, and assistance. Each one of you has,