So says David Reich, and he was hardly alone. Why? It was always likely, in fact almost inevitable. I can’t think of a human expansion where there wasn’t some admixture with the locals. I’m serious: why? I’ve certainly heard arguments to that effect, but they were all silly. Intersterility was quite unlikely, if you look at mammalian hybridization. Lack of Neanderthal mtDNA in moderns meant nothing much, since it could easily have been lost due to selective disadvantage or by chance. The argument that humans were simply too picky to have ever mated with Neanderthals is plain ridiculous: at worst, they were a lot more human than sheep. Even a small amount of admixture would have allowed introgression of alleles with an advantage: we’re seeing a higher level of admixture than that bare minimum but nothing particularly surprising.