What determines if a person is gay or straight? Is it his upbringing? Could it be his group of friends that he hangs out with? Or could it be something that occurs much earlier than one's childhood? Recent findings have indicated that sexual orientation is determined mostly by genetics. According to the authors of our Psych 1001 text book, "it's plausible that biological differences are sometimes present even before birth" (Lilienfeld, pg. 441). The textbook also states that Michael Bailey and Richard conducted a study and found that there was a 52 percent likelihood that a set of identical twins shared the characteristic of homosexuality, compared to only 22 percent between fraternal twins. The higher percentage between identical twins demonstrates that genetics are a higher indication of sexual orientation because identical twins share 100 percent genetics.
CBS covered a story of two sets of twins and the differences between these twins. The first set of 9 year old twins is Adam and Jared. Adam and Jared are completely different in their interests. The movie below describes how Adam's room is pastel colors, with stuffed animals and white horses covering the majority of the room. Adam's behavior is known as childhood gender nonconformity, meaning that his behavior is similar to that of the opposite sex. Juxtaposed to Adam, Jared's room is filled with a G.I. Joe collection and several military toys.
The other set of identical twins is Steve and Greg. Greg is gay while his brother Steve is straight. The mother mentions how there were early indications in the difference between the two sons. Even during high school, Steve admits that he knew that Greg was gay.
Michael Bailey, a psychology professor at Northwestern University, believes that nurture is not a plausible explanation for sexual orientation. These two sets of twins show how even though they are raised in the same environment, their sexual orientation and behavior differs.