Your first three examples are speculative edge cases, to say the least. But your last is interesting - and touches on something I was going to type but didn't.

Your first three examples are speculative edge cases, to say the least. But your last is interesting - and touches on something I was going to type but didn't. Yeah, evolution might be happening there, and not in a good way. There's evidence that smart couples have less children, because they're busy with careers. There's evidence that religious people have more children than non-religious. So yeah, to the extent that evolution is still in play in modern society - we're probably going backwards.