After reading the title of this article, I wondered how long it would take for a “make love, not war” joke to make an appearance. It took two sentences. Many of us will know that there are a ton of theories out there as to why Neanderthals went extinct. Well, a new paper proposed that rather than war, climate change, etc., it may have been about sex. We find Neanderthal DNA in Homo sapiens, but we don’t find sapiens DNA in neanderthals, which suggests that Neanderthals were joining Homo sapiens groups, and this may have left fewer breeding-age people in Neanderthal communities. According to Chris Stringer, “If Homo sapiens were breeding into the Neanderthal gene pool it was very rare, or it was not successful,” the latter alluding to the fact that hybridization sometimes only works in one direction. He went on to say, “Perhaps Homo sapiens groups acted like sponges in absorbing pockets of late Neanderthals, and maybe that, as much as anything else, led to the eventual demise of the Neanderthals as a viable population.”