We have a thing for NeanderthalsZUMA Press, Inc/Alamy Stock PhotoBy Aylin WoodwardIt’s a sex-laced mystery. If modern humans didn’t reach Europe until about 60,000 years ago, how has DNA from them turned up in a Neanderthal fossil in Germany from 124,000 years ago? The answer seems to be that there was a previous migration of early humans – more than...