This occurred to me when this subject first came up: All
societies have a form of incest taboo. If there are a lot
of wives to one husband that would increase the number of children
who were at least half brothers or sisters. In smaller villages or
settlements that decreases the eligible mates for the next generation.
Our society views any relation as close as cousin as ineligible for
mating. That would eliminate a lot of potential mates in a polygamous or
polyandrous society if the population is scattered over a large area
and transportation is treacherous.
Comments??
Debbie