I always worry when they look into homosexuality's genetic roots, honestly... God forbid parents ever have the ability to predict their child's sexual orientation. I know there's an alternate theory that's neither genetic nor psychological -- regarding the balances of chemicals in the mother's womb.

What irritates me is these studies always always always focus on gay men, and it's not clear whether they apply to lesbians, or bisexual women and men. Not that those studies would do me much good either.

Given the complexities of sexual orientation, I doubt it comes from any one source. Probably the causes are just as complicated as the actual phenomena, given the huge range of sexual orientations and gender identities.