Blogs aren't the best places for debate, but well try to make this work as best as possible. This is an ongoing debate with David. See "Dueling David" for the previous round if you'd like to join in, and don't forget to read the comments because that is where David replied.
Naturally Flawed Logic
I never claimed that anything which occurs in nature is OK. After all, there are some pretty horrific genetic mutations which happen in nature. If I had the power to control that, maybe like God, I would probably try to prevent that from happening. But I digress. ;-)
I missed the BBC series on chimps, but, yes, murder and cannibalism happen in nature. Yes, many, if not most or all, of us feel the occasional violent urge like we would want to kill others, even if that feeling is fleeting and not deeply serious. But that's entirely different than sexuality. Let's talk about why.
Sexuality affects us so much that researchers determined that one of the first things we recognize about anyone is their sex. Male or female? This is long before we could even form an opinion on whether or not we should kill them. ;-) Our sexuality is always there. Our urges to kill other people? Not so much, unless we are just insane.
In purely legalistic perspective, your friend's comment is correct. Until someone has homosexual sex, they are not homosexual. But that's not true in the brain and the internalized sexuality which we all think about on at least a subconscious level any time we meet other people. In fact, that's one reason why I know that male homosexuals are natural. Not because I have homosexual desires, but precisely the opposite. I think male homosexual sex is repulsive. If all men had the same sexuality as me, male homosexuality would not exist. Yet male homosexuals do exist, so not everybody has the same sexuality.
You know what else? I can often tell when another man is homosexual. You may have heard of a term “gaydar.” Not always. Not perfectly. But often enough that it's not just coincidence, I can tell. I picked up on it pretty readily with the three gay friends I have, and it's not because they were flamboyant about their homosexuality, or because they made passes at me (although one of them did eventually, I guess his gaydar wasn't working).
You may be of the opinion that men and women think differently. Quite often, the homosexual men I've met have thought differently as well. This is somewhat of a proven fact too. Do a little research, and you will find that our top military language translators are quite often homosexual. That's why policies which exclude gays from the military are actually somewhat detrimental to national security.
An unnatural love for languages and an inclination for interior design are stereotypes of homosexuals for a reason. It's not that all homosexuals possess these skills, but enough do to stand out. And that points to homosexuality as being more than simply a label of someone who preforms the act of homosexual intercourse.
Something else to consider: Roughly 1.7% of human births are intersex, where sexual organs are not clearly male or female, or actually have both sexual organs. About 0.018% of human births have chromosomes which are inconsistent with either male or female. If something as basic as male verses female organs can get mixed up, it must be inherently possible for “masculine” brains to end up in female bodies, or visa versa, or some hybrid of male and female brain.
OK, so all of this points back to homosexuality being completely natural, homosexuals being born with homosexual desires from birth, and God condemning them for those very same desires. Yes, I know, desires and actions are different. You can argue it's still a choice in the end (no pun intended). But if a homosexual man feels towards sex with a woman the way I feel towards homosexual sex with another man, well, quite frankly, that's no choice at all. It's not going to happen.