[Pharmboy]

That was settled by the DNA evidence: the data show that non-African modern humans share 1-4% of their DNA with Neanderthals, so there was indeed some hanky-panky going on.

[varmintman]

God gave us the tools to understand the world around us and the most basic of those is logic. There is terribly little genetic variation in the human race compared to all but one or two other mammals and that is due to some fairly recent genetic bottleneck which reduced the human population to a very small number of individuals, possibly less than fifty or a hundred. If any human group had mixed with Neanderthals AFTER that bottleneck, the variation between that group and all others (humans) would be gigantic.

The only conclusion which is tenable is that there has never been any mixing of humans and Neanderthals, and that any similar genes anybody finds are just artifacts of same or similar low-level components being used by an original designer or designers.