I think you’re missing a trick, there. Anal sex doesn’t lead to reproduction, correct; it, to an extent, inhibits it, assuming a sexual zero-sum game or homosexuality. It’s the most direct affect of reproduction possible; it lowers the chance of it happening. If I as a proto-mammal have gay siblings, then that means that a) I have less competition to mate and b) I have effective “babysitters” to ensure I can go out and do more mating (and have someone protect my genetic offspring).
That would also seem to rule out human-level intelligence as a product of evolution. Or flight, if we may move to other species.
This is a problematic argument for two reasons. One is that we have a lot of traits that don’t lead to reproduction and greater genetic diversity. The other is that you might be wrong. Like I said earlier, if it encourages tighter bonds in the social group, that means more people survive and reproduce, which means more genetic diversity. And someone who isn’t having reproductive sex can still help the group survive without passing on his or her genetic material- although in these discussions people have a habit of forgetting that gay people can and do pass their genes along the old-fashioned way.
I’d have to say I disagree with the assertion that anal (or other types of non-reproductive) sex doesn’t lead to reproduction. I’ve manged 5 kids with my wife, while still managing my fair share of, er, non-standard/non-‘natural’ sexual contact through the years. The thing is, that having sex isn’t about simple procreation…it’s about the bonding. And non-reproductive sex, and the additional bonding can lead to the reproductive kind.
Pretty obviously, since there is still a Greece out there…it’s been in all the papers lately.
The thing is, that having sex isn’t about simple procreation…it’s about the bonding. And non-reproductive sex, and the additional bonding can lead to the reproductive kind.