if a human and a neanderthal had a child, hybrid offspring may have been less fertile, or even rejected by both societies, or even killed. any humans that rape

if a human and a neanderthal had a child, hybrid offspring may have been less fertile, or even rejected by both societies, or even killed. any humans that raped the neanderthals would probably not integrate those neanderthals into their human societies. any hybrid (with neanderthal mother) would probably remain in neanderthal societies.