A GENE has been discovered that appears to dictate the sexual preferences of female mice. Delete the gene and the modified mice reject the advances of the males and attempt to mate with other females instead. SOURCE
Most scientists and skeptics are hesitant to say that there’s such a thing as a “gay gene.” Primarily, this is because the idea of a gene that “makes you gay” doesn’t represent an accurate understanding of how genes work. However, this discovery is about as close as you could get to a single gene that “causes” gayness.
The gene the team deleted is for an enzyme called fucose mutarotase, which adds the sugar fucose to proteins. Park believes that disabling the gene exposes parts of the developing mouse brain linked with sexual preference in adult life to extra oestrogen. The hormone masculinises the brain in mice – though not in people.
Of course, even though this gene doesn’t have the same effect in people, it’s still a compelling and powerful look into the mechanics of homosexuality in the mammal kingdom.