[All-In Flynn]

I don't see this reflected in apes. Ants, yes. Vertebrates tend to invest far more in one batch or litter (to varying degrees) - primates more than most vetebrates, and humans more than any other primate. The beneficial effect of any gene tending against its bearer reproducing must, I think, be of a corresponding degree - not shown.

Now I realise that it may be true that, say, the majority of male apes do not reproduce. Do we then see that such apes as are observed to practice something like homosexuality (can't remember which specific ones, something like 'Barber apes' but I can't quite remember it)are given responsibility for the care of the group's young? And is this role assigned to gays of both genders?

It seems more plausible to me that if there was a pressure exerted in favour of gayness, the (male) gays would far more likely be hunters or soldiers. I can see how this kind of primitive labour division might result in fewer orphaned offspring, which might in turn mean less waste... but it's difficult to model this kind of waste-avoidance as directly beneficial without resorting to group-selectionism.