Human/Neanderthal Sex Only Happened Every 25-50 Years

But that was still enough for all of us (well, everyone but Africans) to end up with a little bit of neanderthal DNA.

Remember earlier this year when we found out that about two-three per cent of most humans' DNA comes from neanderthals? As it turns out, it's likely that genetic material made its way into our species over very few human/neanderthal, umm, interactions, as researchers created a model that determined all that DNA only came from about 430 total encounters of the span of about 10,000 years. All told, that works out to only one human/neanderthal hook-up every 25-50 years, which kind of dampens our hopes that human prehistory was a giant bacchanalia of species sleeping with whatever species they wanted. The researchers say the rarity of interactions is probably due to both species looking down upon the cross-breeders, a fact that must have made those few forbidden encounters so much hotter.