I'm not necessarily disagreeing with you; I know that homosexuality is somewhat influenced by genetics. Which is why I said it has a strong developmental component. It is not 100% genetic, like eye color or skin color.

All of this said, twin studies are highly unreliable and I don't recommend them as hard and fast evidence.

Why do you believe this? All the evidence I've seen is that intelligence is mostly genetic, and providing an intellectually stimulating environment (beyond normal schooling, I suppose) will have very little effect.

I'm not talking in terms of raw intelligence potential per se. I'm talking about how that intelligence is used. I'm sure that "medieval theocracies" had plenty of smart people, in fact they were almost definitely just as smart, in raw intelligence terms, as people are today. This is why I'm saying the key to a successful society lies in providing a good cultural environment for children to grow up in.