How to explain homosexuality? Options

[Call911Quick]

OK, so as not to step on any toes, let's assume evolution is how the world came about.

Now, homosexuality goes against every theory of evolution that has been thought up. There are certain lizards somewhere that are all female, but they don't have sex. They lay unfertilized eggs, so essentially they clone themselves.

We're studying how and why sex and sexual reproduction developed and everything. So, obviously, homosexuality isn't "programmed" into us.

So what makes a guy gay? Is it increased levels of estrogen? Decreased levels of testosterone? Is it psychological/self-induced, or can you not help it?

I don't understand how any guy can be gay. Lesbians turn me on, but I mean... Ever take a REALLY big shit? Imagine that, but backwards. And continuous. I mean... it's like watching two porcupines have sex. Wait, that's a bad metaphor, more like... watching gorillas have sex.

[Comptine]

Didn't we have like 20 other topics like this?

But, there can be like a genetic link or physical/bodily link to homosexuality. Concordant twin studies have shown that with identical twins, if one was gay, the other was gay too in about 50% of the cases. That percentage goes down when fraternal twins were studied.

Let's say that it is genetic: Some genes in our DNA turn on or off or mutate. Though genetic mutations are rare, it could explain how "genetic homosexuality" can happen.

Let's say it's nurture: If someone grew around homosexual ideas and behavior, and they end up homosexual, then you can see how environment impacts the behavior/sexuality of someone. However, how do you explain how there's a large percentage of gay people who come from very homophobic backgrounds?

I personally think it's wiring and chemicals inside the brain. Straight Bob looks at a woman and he gets happy chemicals released or arousal chemicals released, Straight Bob would be inclined and more attracted to women. However, if Gay George look at a man and got the same reaction Straight Bob got from looking at a woman, then he might be more inclined towards men.