Assumptions past and present about our prehistoric behavior reflects very thin evidence. Still, this is encouraging.

Before we had sequenced the Neanderthal genome and discovered our mixed ancestry, the traditional story of how Homo sapiens came to rule the western half of Eurasia was a lot uglier. Basically, scientists believed that humans had come out of Africa and killed off every other hominin they met. Maybe they didn’t actually stab them in the face — though anthropologists like Richard Klein do believe there may have been a genocide. But as evolutionary biologist Ian Tattersall has said, a more likely scenario is that humans just out-competed the local Neanderthals, using up local resources and driving their big-boned cousins to extinction.

Now that we know about the Neanderthal ancestry in Europeans, we have a third possibility, which is that Neanderthals assimilated into Homo sapiens. Sure, there may have been competition between the two groups but they had families too.

This is where the philosophical importance of Neanderthal/Homo sapiens sex comes in. We may never know the real story of what happened between early Homo sapiens and the other hominin groups they met outside Africa. Any scientist who claims to know the truth of these events is, well, a bad scientist. Like all histories, the tale of our distant forbearers is an interpretation, based on available evidence. And the story we choose to tell ourselves about that evidence matters a great deal.

So, why does it matter that Homo sapiens had sex with Neanderthals? It matters because now we have genetic evidence that humans as a species don’t always kill and destroy what we don’t understand. Sometimes, we fall in love and settle down instead.

More: Why Does It Matter if Homo Sapiens Had Sex With Neanderthals?