[syriacus]

but human homosexuality runs completely counter to the basic premise of his argument: that sexuality is flexible in nature "to solve the problem of how to survive and make as many babies as possible."

Good point.

[donh]

but human homosexuality runs completely counter to the basic premise of his argument: that sexuality is flexible in nature "to solve the problem of how to survive and make as many babies as possible."

This is a pretty shallow assumption. The problem is to get your genes successfully into the future. That may not necessitate "making as many babies as possible" at every turn. If you are related to someone you gather resources for, aren't you contributing to the survival of some of your genes?

If nature is so dead set against non-breeders, how do you account for grandparents living past their reproductive years? Shouldn't natural selection eliminate them? What good are they if they can't breed?

In point of fact, there are many examples in nature of genetically useful non-breeding choices. Wolves under resource pressure, for example, change from mated pairing into alpha pair only, with the females grounding their pudenda, and the males turning queer, making more resources available for the alpha pair's kits. One wonders how social ants and bees could possibly exist if the every-gene-for-himself strategy is universal. How did solitary bees give up their breeding rights to a queen? Ans: they turned queer, just like wolves do--only for them, it became permanent.