Just for fun (haha /cynicism), I googled 'homosexuality is not a choice' and 'homosexuality is a choice' just to see what came up in the first couple of pages. For the former, I came up with a site for religious tolerance (yay for that one!), the American Psychological Association, an Australian Pyschology educational site, a debate site and some sites supporting LGBT rights. For the latter, it came out with a Conservative Wiki, a debate site, and with the exception of the medical sites, those other ones I already listed who claim that homosexuality isn't a choice. So, on one hand we have recognised national health organisations declaring that it is not a choice and and on the other, a politically biased Wiki. Doesn't quite measure up somehow does it? I think I also googled something similar about it being a choice and it came with the site NARTH, who claim they can cure people of gayness with therapy.
Plus the fact that scientists are finding more and more common traits in gay men that aren't in heterosexual men. It's so stupid though, the more science comes up with evidence that homosexuality and bisexuality is genetic and not a choice, the louder religion argues that they can 'cure' you of your debased and evil predilections (their words, not mine), despite proof that such 'therapy' can actually do more harm than good.
This line of thought was of course brought about by someone's comment on the HYS (I really should stay away from that place, it's like a vice to me) that homosexual parents were more likely to turn their adoptees gay. ?? Oh please, give me a break. Where's the evidence for that? Where? What's that? You mean you have no evidence for it and it's just a bigoted opinion? Surprise, surprise. I once heard someone respond to a claim like that, that if all children had their parents' sexuality, there would be no gay people. Best comeback ever, and accurate.
Funnily enough, two years ago the Karolinska Insititute in Sweden did a study on homosexual/heterosexual brains and found that homosexual men have a brain that is identical in size to heterosexual women and were smaller than that of heterosexual male. Homosexual women had a brain that looked and was of similar size to a heterosexual male. Lesbians and hetero males have more nerve connections in the the part of the brain that regulates sex (I think it's called the amygdala),whereas hetero women and gay men have more neural connections. And from what I understand, these things are formed due to genetics in pregnancy. At least that's what certain institutes in the US (can't remember which ones exactly) have discovered through research.
Then of course, there's the age old question 'why would LGBT people choose to be that way knowing all the ridicule and persecution they face from others?' I've never, ever gotten a satisfactory answer from someone who believes it's a choice. In fact, more often than not I don't get an answer at all, they usually just dodge the question, at which point I stop debating and leave.
Anyway, I'll climb down off my soapbox now, I just needed to vent.