[ahayes]

My position is that there was not much of this kind of protection going on, before people even understood that sex results in babies, and before people acquired scruples about sexual activity.

Why not? High-rank male chimpanzees control access to the females in the group, and they certainly don't understand paternity.

[Graymatter]

>>High-rank male chimpanzees control access to the females in the group, and they certainly don't understand paternity.

That's different. It's within the group, it's a social thing. Not consciously practiced for the protection of the bloodlines. Not to make sure they have good healthy offspring.
You need some kind of a system, else the young fellows are going to bash their elders' heads in, and that's bad for business.
Besides, any comparison to animals is going to miss the mark, because even the Neandertals were sentient beings with conscious motives.
At least---I think so!