Originally Posted by Kaioo
Well, a bit of opinion and a bit of scientific fact splayed in our local paper a few years back stated that it was due to hormones most of the time, as you don't discover your sexuality until you're a teenager...
False association. You don't begin to have sexual urges until puberty, but that is a completely seperate issue from sexual orientation. For example, I had my first crush when I was 8, well before puberty. Along the same lines, I know a girl who happens to be a lesbian who, when she was 7 or 8, used to imagine herself as the knight riding in to save the princess and get a kiss rather than the princess waiting for the knight, and who had crushes on other little girls in the same vein as my 8 year old crush. The difference is that it doesn't actually *mean* anything until puberty, when crushes turn into proper romantic attraction and lust and we start to learn what that means. It's not that we don't have a sexual orientation, it's just that that's when we begin to understand what those funny feelings when we look at the boy/girl we "like like" really mean.
Edit: As to Doodlebob's standpoint, I don't think any testing has actually been done along the lines of non-genetic or pre-natal causes for homosexuality, so whether other things can influence your orientation is a matter that still needs to look into. However, as someone with several friends and two family members who aren't straight and who has directly questioned them on this, I can tell you quite certainly that no one makes an active, conscious decision to be gay.
If you want my personal opinion, I think it's partially societal, and that in fact most of us are somewhere in the middle of the Sliding Scale of Bisexuality. The only reason we don't recognize it is because of the personal stigma. Look at Kaioo, who openly admits to having had gay thoughts but outright states that he wouldn't go there because it weirds him out. I can say exactly the same thing. But if you look at, say, ancient Greece or Japan, do you think they had that same stigma?