Rallem wrote:
"they could breed with modern man as well, but the offspring were like mules and were sterile".
There's no way we can know if that was true. It's just a theory someone thought up as possible support for the belief that they didn't form hybrids. However we do know they swapped technology so they presumably interacted in some way. Just because their skeletons were a bit different doesn't at all prove they couldn't hybridise. Breeds of dog look very different but have no trouble forming hybrids, as many pedigree breeders know to their cost.
Also; "I will not swear to this combination's fertility". As species drift apart in their ability to form hybrids usually the male hybrids become infertile before females. It's not usually the direction of the hybrid, i.e. male horse, female donkey or the other way round. Some female mules are fertile but have to be bred back to either a horse or donkey male to produce offspring. Hybrids between bison, cattle and yaks are another example of the phenomenon.
Enough is known about dna and enough dna has been recovered from the fossils of neanderthal man to know that their dna was too different from ours. This is from recollection though of a television show on the learning channel or one of its affiliates, so I will not attest to my message earlier, because some of the shows reasoning seemed flawed to me.
