A genetic study that has concerned many people is the search for the ‘gay gene’. The finding of this gene began in the 90’s and is still in question to whether the gene exists and if it truly influences sexual orientation. Several studies have been completed that look into sexual orientation through behavioral and molecular genetics. Most of these studies, however, have failed to be replicated and they bring about ethical issues.
Simon LeVay, a neuroscientist who studied brain functions and sexual orientation (Wikipedia contributors, 2014), published an article, “A Difference in Hypothalamic Structure Between Heterosexual and Homosexual Men,” in 1991, that suggested a biological reasoning to sexual orientation. The hypothalamus, which is a region of the brain that is involved in sexual behaviors, was assumed, by LeVay, to be a biological substrate for sexual orientation (1991). LeVay suggested that the anterior hypothalamus “participates in the regulation of male-typical sexual behavior” (1991). LeVay’s research indicated that there is a difference in volume of the third interstitial nucleus of the anterior hypothalamus (INAH 3) between women, homosexual men and heterosexual men. INAH 3 was found to be twice as large in volume amongst heterosexual men compared to that of women and homosexual men (LeVay, 1991). LeVay concluded that the INAH 3 is dimorphic with sexual orientation, meaning that INAH 3 is physically different when comparing sexual orientation amongst groups of individuals.
In 1991, a behavioral geneticist, Michael Bailey, proposed that genes may contribute to homosexuality in males (Wickelgren, 1999). Bailey found that 52% of identical male twins were homosexual compared to 22% of fraternal male twins (Wickelgren, 1999). Bailey reasoned that homosexuality was influenced by polymorphic genes (Rice, 2006). The twin study exerted by Bailey suggests that there are genetic and environmental factors that influence the expression of a homosexual trait (Rice, 2006). From this study, Bailey implied that homosexuality was frequently inherited from the matriline (Rice, 2006).
Another study that was conducted in 1993 by Dean Hamer and his colleagues suggested that there is a correlation between homosexual orientation and the X chromosome. Hamer and his colleagues set out a research to determine if male sexual orientation was genetically influenced. They were already aware of LeVay’s study on the INAH 3 difference amongst homosexual and heterosexual men (Hamer, 1993), and wanted to apply further knowledge from a genetic level. Their data indicated a correlation between the inheritance of genetic markers on a specific chromosomal region (Xq28) and sexual orientation amongst homosexual men (Hamer, 1993).
Hamers study consisted of 76 homosexual men whose pedigrees were traced out in order to identify other homosexual family members (Pool, 1993). Hamer mentioned that when they collected the family histories for each homosexual individual, they...