In my ongoing quest to blog more often about LGBT issues, allow me to cover a bit of gay 101: Homosexuality is not a choice.
In fact I find it really hard to imagine choosing homosexuality. Do you ever look at people, and say to yourself, "I want to be attracted to this person"? I've tried that, it doesn't work. Who you're attracted to isn't something you pick out, it's something that just is. At the very least, we know for sure that it isn't a direct choice. If it were easy to choose one way or another, I think far more people would be heterosexual. At first, most gay people experience a lot of distress due to social ostracizing and homophobia. So if it were so easy to choose, most people would go down the easy path and make themselves heterosexual. This does not happen.
In fact, there appears to be a genetic component to it. I'm not very familiar with the long and complicated science of the causes of homosexuality, but I've gotten the impression that genetics and prenatal conditions play a big role. I've heard that homosexuality is correlated with left-handedness (which, incidentally, has also been historically discriminated against). And for men, it also correlates strongly with the number of older brothers. These are things which are decided before you're born, so they obviously can't be the result of a conscious choice.
But the evidence is somewhat mixed and inconclusive. I certainly do not take it as an article of faith that homosexuality is genetic. I am not a genetic determinist. But that still doesn't necessarily make it a choice. It could just be random, or determined by indiscernible factors, or determined by uncontrollable factors. There isn't always a nice chain from cause to effect (ie genes --> gay). It's usually much, much more complicated than that, making it essentially appear random.
Perhaps homosexuality could be an indirect choice? Perhaps there is something we can do to affect it? Perhaps so, but we have no idea what that something is. That something may just as easily make a person more gay or less gay, or its effect may differ from person to person. Or it will do nothing at all. As an analogy, imagine you're on a game show, and you have to open one of three doors. One of the doors has a fancy car behind it, and the other two have goats. You get to choose which door to open, but it's not much of a choice is it? Without knowledge of what's behind each door, without knowledge of the consequences, you can't really call it a choice.
But there's another important point to be made here. Even if it were a choice, so what? That doesn't make it wrong. I'm no ethicist, but I understand that moral culpability requires two things: the choice must be conscious, and evil. In fact, part of being gay is a conscious choice: sexual identity and sexual behavior. But it's hard to see these as being evil choices. For sexual identity, it is my belief that identity should be accurate and reality-based. By that standard, identifying as gay when you're gay is the right choice, and denying it is the evil choice.
As for sexual behavior, I fail to see how having a same-sex relationship is evil. Refusing to pursue such a thing when you want it is like hitting yourself with a mallet. I have no problem with celibate gays; I think people have their reasons. But it's not what I'd call an admirable choice. Now, sexual promiscuity is less straightforward, but that's not what I'd call homosexual behavior, it's what I'd call promiscuous behavior. That's a whole 'nother topic, which I'm unlikely to cover.