Genetics and Sexual Orientation
There has been interest among researchers in determining a biological basis for complex behavioural traits, including sexual orientation. One area of study has been how developmental processes may affect psychosexual orientation in adolescence and adulthood. For example, testosterone exerts an influence on the development of the central nervous system. It is thought that this brain imprinting may in turn affect psychosexual orientation.
Another area of study has been the search for a ‘gay gene’. However, studies in this area have been inconclusive and debate continues. (60) The search for a genetic basis for sexual orientation is controversial for many reasons, one being that it is unclear whether a genetic basis will serve to enhance or diminish the stigmatization of sexuality that occurs in some societies. (61)
http://www.who.int/genomics/gender/en/index2.html