Gay Gene

Plato may have offered the first explanation of homosexuality as an inborn trait in the Symposium, written in the 5th century b.c.e.: he suggests that all humans originally were paired, and homosexuals are the separated halves of male-male pairs. Two pioneers of the modern study of sexuality, Karl Heinrich Ulrichs (1825–95) and Magnus Hirschfeld (1868–1935) also believed that homosexuality was an innate characteristic. Interest in discovery of a biological explanation for homosexuality remains strong in some quarters, and beginning in the mid-1990s, several scientists have announced discovery of results which would suggest a biological basis for homosexuality, although none of these claims have held up to sustained scrutiny.

In 1991, Simon LeVay published results from a series of autopsies which found that the hypothalamus was smaller in homosexual men than in heterosexual men. This study has been criticized on many grounds, including the fact that the homosexual men in the study died from AIDS, which is known to affect the brain; in addition, other studies have failed to replicate his results. In 1993, Dean Hamer claimed that his studies of self-identified homosexual men and their family members suggested the presence of a “gay gene,” in this case a set of markers on the X chromosome, which was highly prevalent although not universal among the gay men in his sample. Hamer's results received a great deal of publicity at the time, although interest has lessened as subsequent studies have failed to replicate his results and the design of his original research has been criticized.

Most modern theorists believe that sexuality is a complex human behavior which cannot be reduced to a simple biological or genetic explanation. Another question whether the discovery of such an explanation would be good for the gay community. Some believe that establishing homosexuality as an inborn characteristic would lead to greater acceptance and stronger legal protections against discrimination such as that afforded to people based on their race or gender. Others argue that it could lead to further discrimination, including termination of pregnancies if a fetus was found to be carrying the “gay gene”, or early behavioral interventions on boys carrying that gene.