One more piece of evidence has been added to the debate on whether there was any interbreeding between Neandertals and early modern humans. Around 50,000 years ago, small groups of anatomically modern humans migrated out of Africa and began to colonize the rest of the world. Known as Cro-Magnons for the site in France where the earliest remains were found, these early humans co-existed with the Neandertals then living in Europe until the Neandertals became extinct roughly 30,000 years ago. What happened and why—did the two groups war, did they mate, did they even meet?—has been an enduring puzzle...