I forgot about that comment.... and i don't remember making a rebuttal so here is my delayed rebuttal; Homosexuality has become more or less excepted through out American Society. Due to this fact you would normally expect less people to come out of the closet every year, the opposite is the reality. I never specified when it would be weeded out only that there would be signs of it doing so.
On a related note, genes must encode something (pseudo-genes aren't genes and don't encode but genes by definition must encode one or more traits, that doesn't mean several genes can't be used to make up a singular trait) so new genes are VERY rare (alleles are a different story and are variations of a gene i.e. eye color). Let's assume their is indeed a sexual orientation gene with 2 alleles, 1 gay 1 straight, it would most likely be a relatively new gene due to the fact that if it developed in our early history we would have had too few mating pairs to survive all the plagues, famines, predators, ect. However that can't be the case b/c every ancient civilization has some form of homosexuality, Athens is a prime example but if you look at the Native Americans (& there was barely 100 people who crossed the land-bridge 17k years ago, limiting the time span of said mutation much less likely both forwards and backwards) they had men called Berdaches, or the third gender. So technically there could be said gene, though the likelihood is exceptionally small. Also, why can't they find it?