There was the genetic compatibility, with advantages that were manifest but not well understood.

(The prospective mother on the tentatively titled "Make Me a Mum" show would select the winner based on looks, intelligence and genetic compatibility.)

Yet it was possible that they had mutated beyond genetic compatibility.

They are direct phenotypic benefits, sensory bias, Fisherian runaway, indicator traits, and genetic compatibility.

This makes testing components of genetic compatibility difficult and controversial.

A controversial but well known experiment suggests that human females use body odor as an indicator of genetic compatibility.

Similar to the humans of the odor rating experiment, animals also choose mates based upon genetic compatibility as determined by evaluating their potential mate(s) body odor.

Some animals, such as mice even assess a mate's genetic compatibility based on their urine odor.

"Faint to you, and strong to me, but don't you understand, that's probably some marker of genetic compatibility."

"Mona, what the hell do you know, child," demanded Randall, "about genetic compatibility?"