Ever since we briefly discussed the “gay gene” in class and whether or not the discovery of such a gene would be beneficial or detrimental to homosexuals, I have been extremely curious as to what kind of scientific literature is out there that discusses the biological basis of homosexuality. The study that I found (it starts on page 2) focused on four cell groups found in the anterior hypothalamus, which is suggested to be involved in the regulation of sexual behavior and in the generation of male-typical sexual behavior. It has been found that two of these cell groups have larger volumes in human males than in females, suggesting these cell groups play a part in sexual orientation. This study found that one of these two cell groups was also twice as large in heterosexual men as homosexual men, suggesting a possible biological explanation for sexual orientation in male humans.
http://www.isds.duke.edu/courses/Fall02/sta240/THmidt.dir/sciencearticle.pdf