Sick Sex is Killing Humanity

If our beautiful, intelligent, tools-manufacturing ancestors had evolved as Nature planned it, we would now be almost perfect. But they had a bad, sick side, in fact they were sex-crazy perverts that would immediately mate with any ambulant creature with a hole or a hose between their legs. So they mated with brutish, raw-meat devouring Neanderthal animals, who could not speak an intelligent word, and injected to our genome their primitive vital essence. 

Their incandescent sex-hunger made them approach and mate with the even more primitive Denisovans, veritable gorillas hiding in Siberian caves. Because of their sinful nature, half of humanity now looks like gorillas. 

And if mating with these two proto-hominids did not satisfy their degenerate concupiscence, they maintained secret affairs with a third and a even with a fourth pre-sentient species in Africa, endowing their unfortunate descendants with a monstrously prominent ass. Humanity is doomed, the Planet of the Apes (see pic above) is our sad future.