Synopsis of the Big Bang Theory's Main Characters Dr. Leonard Hofstadter Experimental Physicist at Caltech Best Friends with roommate Sheldon Come from a family of over-achievers; feels overshadowed by highly accomplished brothers and sisters and aims to be considered accomplished by his mother Is the most socially adept of the four male scientists Has a crush for Penny, whom he eventually dates Dr. Sheldon Cooper Theoretical Physicist at Caltech Best Friends with roommate Leonard A child prodigy, holds multiple university degrees, received his PhD at 16 Shows traits of Asperger's syndrome and Obsessive Compulsive personality disorder Has both an eidetic memory and extensive knowledge of multiple fields Is dating Amy, who shares similar intellectual and personality traits with Sheldon Penny Waitress at the Cheesecake Factory Moved from Nebraska to California to become an Actress, in recent seasons she has taken acting lessons to achieve her goal Did not go to college/university, but in recent seasons has enrolled in community college While she does not have a higher education, she has the most "street smarts" of all the main characters and is extremely knowledgeable about pop culture Is outgoing and has had many romantic relationships; is currently dating Leonard Howard Wolowitz Aerospace Engineer at Caltech Holds a Master's degree from MIT; gets constantly picked on by the other male characters for his lack of PhD; trained for a mission to the International Space station Best friends with Raj Is a womanizer; thinks he is a ladies' man, but fails spectacularly each time he attempts to pick up a woman Lives at home with his mother (until he marries Bernadette) Eventually falls in loves and marries Bernadette, toning down some of Howard's womanizing personality Dr. Rajesh Ramayan "Raj" Koothrappali Astrophysicist at Caltech Best friends with Howard; which at times appears that they have a homosexual relationship with one another Is from an affluent family in New Deli, India; one of Raj's sisters Priya dated Leonard briefly Has selective mutism which arises when Raj attempts to talk to women. He is unable to do so (besides his mother and his sister) unless he is under the influence of alcohol (or thinks he is under the influence of alcohol) The only one of the main characters without a romantic interest, however in later series he has dated Dr. Bernadette Rostenkowski-Wolowitz Microbiologist for a pharmaceutical firm Introduced to the series as being a co-worker of Penny from the Cheesecake factory; where she worked part time to pay for her graduate studies Penny set up Bernadette and Howard on a date (whom she eventually married) Is usually friendly with everyone, yet can show signs of mania Has an aversion to children due to the necessity of helping her mother raise her siblings when she was younger Is good friends with Penny and Amy; the three will have girly dates when the boys have "guy nights" Dr. Amy Farrah Fowler Neuroscientist, specializes in working with monkeys analyzing addictive behaviours Introduced to the series as being a match to a Sheldon's fictitious online account from a dating website set up by Howard and Raj Shares similar personality traits to Sheldon, yet is more personable Is in an unconventional relationship with Sheldon; aspires for it to be more physical than it is Is friends with Penny and Bernadette, yet considers Penny her "bestie" and holds Penny to high esteem; she can be obsessive and inappropriate with acts of friendship towards Penny .