Scientists can tend to get into weird little areas of research; perhaps the meticulous nature of the work lends itself to that. In any case, in an attempt to understand estimates that modern Europeans share between 1 and 4 percent of their genes with Neanderthals and that people outside Africa shared more genetic variants with Neanderthals than Africans. Africa is considered to be the cradle of humanity, where humans first became, well, human. So, the thinking is that early humans still engaged in the old bow-chicka-bow-wow with their Neandethal brethren after they migrated from the African continent, as recently as 37,000 years ago. Ah, science.