gay genes
In response to a discussion forum thread starting "Are gays born that way?"
Depends how you define "Gay"...
If you're talking about desire and internal sexual response, then I think there's sufficient evidence of a genetic component AND of in-utero hormonal exposure being a factor. For the first, my belief is mostly derived from the popular press - I know how (in)accurate that is as a source, but in this case I choose to believe it. As for the hormonal exposure, I read a lot of technical papers about that some years ago. I was quite convinced, but the info is dated.
I've also thought that perhaps the genetic factor works, not at the level of determining the gender of the object of desire, but in the way the object of desire is imprinted, which would sway the probabilities. Think of that what you will!
All that, in my opinion, gives *some* people a predisposition from birth (nature). The remainder would be explainable by psycho-social factors (nurture - in family AND society). You could also argue that families and societies are the natural human responses to the problem of cooperation for survival, so any human response (including homosexuality) to the human environment is "nature" just as much as the physical composition of the body. We all were "born that way" in the sense that we are organisms that have the ability to create our own response to the environment (as opposed to acting from instinctual "hard-wired" responses).
If you're talking about the sexual activities that a person engages in, I believe that's a personal choice. Of course, the choices that seem evident/available to a person are also heavily influenced by family and society (nurture again with same rider as above).
So, that's my answer to the initial question, plus a mild expansion. But what's more interesting to me is "why is the question being asked?" Now, I'm damned curious about the human body, the human mind, how it all works and why people are the way they are. That makes it a reasonable question for exploration (which has been done here from a number of interesting angles). It doesn't make it a question that has a definitive answer (not even mine, straddling as many fences as I can swing my leg over), and it puzzles me that some people seem to expect that result.
Some of the ghosts among the answers sadden me. A belief in genetic predisposition or even determinism isn't necessary to make someone's homosexuality real or right. I believe that it's real and right for some people, regardless of how it comes about. And believing it to be a personal choice isn't a judgement that it's either a BAD personal choice or a GOOD personal choice. It's just a choice.
Someone earlier asked for a personal perspective from a bisexual. I don't know, and it doesn't matter (except as an intellectual curiosity) whether I was "born that way". In the wider sense, I'd have to say that it feels like I was - the curiosity that has driven much of my sexual behaviour has been with me since I was very young - long before it was turned to matters sexual. The fact that both women and men can arouse my desire has been with me almost as long as I've known sexual desire. Men slightly longer (by a few months), but it's easy to attribute that to social influence! I don't think those specific desires (or even the tendency towards them) have been present since birth, though.
I've loved widely and well, and don't regret it, though these days sex is a lesser factor than it used to be.