> It would be more interesting to debate the causes of heterosexuality.
Well the cause of heterosexuality seems obvious enough. Making males want to fertilize females will cause babies which spreads the "make male want to fertilize female" mechanism creating genes. So a mutation that makes genes that cause such a feeling will spread.
It's a fairly direct linkage so one could see how genes causing it could reach fixation (and indeed, variations of this desire reached fixation hundreds of millions of years ago).
Conversely, genes that result in, say, mice being sexually attracted to cows wouldn't reach fixation, leading to them being very rare in the mouse population. So most animals will be most attracted to things that have the highest chance they can make healthy offspring with.
That's an evolution 101 explanation of why heterosexuals are not extinct, which is fine as far as it goes. It's not a causal explanation of what makes people straight.
In fact, no-one knows what makes people straight, gay, or otherwise. So there is not much to talk about, from a purely scientific point of view.
But anyway, that was an aside. You haven't responded to the main point of either of my comments. If you really are only interested in having a debate about the causes of homosexuality, I'm not the person you're looking for (and the comments on this article aren't the place for it).
Well the cause of heterosexuality seems obvious enough. Making males want to fertilize females will cause babies which spreads the "make male want to fertilize female" mechanism creating genes. So a mutation that makes genes that cause such a feeling will spread.
It's a fairly direct linkage so one could see how genes causing it could reach fixation (and indeed, variations of this desire reached fixation hundreds of millions of years ago).
Conversely, genes that result in, say, mice being sexually attracted to cows wouldn't reach fixation, leading to them being very rare in the mouse population. So most animals will be most attracted to things that have the highest chance they can make healthy offspring with.