The Starborn manipulated human genes? When?

Around 165,000 years ago the Starborn called Morningstar visited the Solar System. While all Starborn are intensely interested in the Great Game, they do have specialties. Morningstar considered itself a toymaker. In other words, it was a genetic engineer. On Earth, Morningstar found many species of humans. Two in particular interested it. In the glaciated north, there was a furred, fierce predator with just the rudiments of society - what we now call Homo neanderthalis. In the still-warm equatorial regions were small populations of a cooperative, peaceful, hunter-gatherer people, Homo erectus. Morningstar wanted to combine the fieceness and intelligence of the Neanderthals with the close knit tribal mentality and year-round fertility of the southerners. It knew that those characteristics (ferocity, intelligence, tribalism and population pressure) are the basic building blocks of world war. Unfortunately, the offspring were infertile when the two species were bred together.  more