Now, having run a successful LGBTQA support group in my town (And one online) I've heard just about every rhyme and reason for anything and everything queer. First things first, for the people who think that not acting in non-heterosexual activities, makes the person still straight, you may want to consider people who are raped, and people who experiment. So, let's say you're a straight virgin guy (As probably most of the users here are, maybe not so much the virgin part, but hear me out) and Mike Tyson decides he wants to get funky with your ass, and assuming said ass funkiness occurs, does that make you gay? you've never had sex with a woman, and you've only done it with a guy, consensual or not. By some of your logic, that would mean you'd be gayer than Liberace's anus. Obviously, that's flawed as fuck...
Now, what about someone who's curious about their orientation? Maybe the same hypothetical person from above has been with women, but is curious about doing the deed with people of the same sex, so, he tries just that, and let's say he's not into it at all after trying, does that make him bi because he tried? nuh-uh
It's all about attraction, or as I like to put it "It's not WHO you do, it's WHY" Look at gay-for-pay porn stars, sure, they engage in gay sex, but only for pay, and wouldn't do it elsewhere, because they're not attracted to men. Look at all the women in the 90's who jumped on the trend that it was "cool" to be bisexual (Both my sisters have actually done that) Years later, when the fad died down, most the women stopped doing that, what are they? I'd say they're straight
Now, for causes there's been proof (I'm sure you can find it, I CBA to do it this early in the morning, haven't even had breakie) That bisexuality, homosexuality, pansexuality, asexuality, and just about anything to do with orientation AS WELL as transgenderism, comes down to a set of hormonal bathes we receive in the womb. Basically, if one set of these bathes messes up, you're bi, if another specific set messes up, you're homosexual, if another does, you're bi/pansexual, if another messes up, you're transgendered, in the sense of being gender queer/fluid/transvestism, if another set messes up, you're transsexual (Like my awesome self) There's a bath for asexual people as well. Now all of this is caused by stress in the mother while carrying the young. This has been proven in animals other than humans (Yes, we're animals too) In labs, you can actually create queer animals from inducing stress in the mother at different points in development, this is actually much easier in animals that are naturally fidgety and stressed, like rats and dogs (They're actually the most likely to be transsexual out of all animals, in fact, you've probably seen a few transsexual dogs, female dogs who lift a leg to pee, and male dogs who squat) This is the strongest argument I've seen for nature being the cause of anything queer
Now, there's also another theory (I say theory, because I've yet to see proof, but it does hold water) And that's that we're all actually pansexual to start with, yep, that's right, you're attracted to everyone, regardless of gender, or sex, BUT the attraction may be SO small, it never comes up. Let's take our hypothetical forum-goer from earlier, he identifies as being straight, alright, with this theory, he actually does like men, women, intersexed people, transsexual people, the whole nine-yards of humanity. BUT the attraction to every one but females is SO little, that it may never, ever come up (Ie, he may never become attracted to anyone other than women) But, maybe he's got a man-crush on Jason Statham (Yeah, I watched Death Race last night, so shoot me) He may find something particularly attractive about Mr Statham there that it actually overpowers the lack of interest in men, and appear as like I said, a "man-crush" You actually can see this all the time on Youtube, but I'm willing to bet most of those "I'd go gay/lesbian for him/her" Are just for attention, some are probably real.
Also, another thing to note, is that sexual orientation is NOT trinary, it's not just hetero/bi/homosexual, it's a continuum, a sliding scale if you wish
That's my tw-- *looks up at the size of the post* That's my five cents on all of that
TLDR, Nature people, nature, and you're all as queer as a 3-dollar bill ^_^
Oh, also a neat fact, giraffe's are the gayest animal ever, 95% of recorded couplings are male and male, 1% is female and female, so, 96% of recorded couplings are homosexual... interesting, no?