[iguy]

I think you may be responding to a stronger, clearly wrong, hypothesis... in which some virus landed on Haight-Ashbury in 1965? And this is kind-of what I'm arguing against -- ruling out a whole line of thought because you take offence at some version.

Every STD has a massive incentive to alter sexual behaviour. Some do: Syphilis makes you horny. And we probably haven't found all of them: if AIDS was no worse for you than Toxoplasmosis, would we have tracked it down? So maybe a whole lot of sexual behaviour is influenced by viruses, maybe in lots of animals. Where would you look to test this? At behaviours which don't seem obviously motivated by standard Darwinian concerns.

Certainly this is a tentative idea, nobody should get too attached to it. Probably there are people saying this more politely than Cochran. Some of us like the blunt style, it wastes less time.