Expert: Walter Hintz - 1/27/2007

Question
Do polygamy and incest have a biological/genetic cause in humans, or are they 100% choice?

Answer
Very interesting question Fred and I am afraid that the jury is still out on this one. First: polygamy:  It would seem to be in the best interest of a species for a male to mate with as many females as possible and it would appear that many males are always trying to do so.  On the other hand from the female standpoint it is in the best interest to select only the best males.  Some anthropologists feel that among prehistoric people monogamy was in the best interest of the species because the man had to constantly scrounge for food while the female had to remain in the "cave" caring for the young.  Life was tough and caring for a lot of females and children was not conducive to survival.
The sex drive however is second only to thirst however and it is certainly biological. Monogamy seems more driven by mores than genes.
 Incest is discouraged in almost every culture.  The taboos on incest however are probably practiced due to learning and not nurture. From a biological standpoint problems that arise from inbreeding are subject to natural selection. A genetic defect is less likely to be passed on.  Only in the human animal is incest not supposed to be practiced.