And a lion and a tiger to make another sterile creature (a liger?), what non-human animal can human’s mate with to produce a similarly made offspring? I would guess Chimps and possibly Gorillas. Has there ever been any evidence of this out in the wild?
Just because it works with some fairly closely related species, there’s no reason to assume that it should also work for other pairs of species that are separated by the same distance in the taxonomic tree, because taxonomy doesn’t solely (or perhaps even primarily) concern itself with genetic difference/similarity.
I understand what you are saying, but that is not answering what I was trying to ask. I gave examples of species closely related genetically (which also happen to coincide with the species taxonomically) and don’t see why it wouldn’t work with humans too. It is kinda oogy but this board seems to relish in the oogy factor at times. 
Hmm, I now see another thread bumped that I didn’t see before that has better links. The links are here and here. I didn’t include the other thread because it is on the first page still. That’ll learn me not to do a search. Hyuk Hyuk.
In general, matings within a species will result in fertile offspring; matings between two species in the same genus will result in “mules” (in the generic sense – viable but sterile progeny). Homo sapiens is the only living species of genus Homo, and probably the only extant species in its family (Hominidae).
Since a similar topic is being discussed, I’ll close this thread and direct further comment to the other: Half-man, half-ape?
bibliophage
moderator GQ