Thursday, September 06, 2007
More Women in the Family Tree
The TierneyLab blog over at the NYTimes has an interesting post about the genetic evidence that there are more women in our individual and collective family trees than men. The sociological explanation is that, in the past, lots of men had no offspring (killed in war, killed hunting, killed fooling around, had bad B.O., etc.), thus the remaining (fewer men) had the job to help the unmatched lonely women have children. So, historically, the reproductive men had more children per person (through multiple partners), than reproductive women had per person. Over the generations, descendants of these men married each other. Thus these men would should up in multiple ancestral lines with different female partners. As a result there are fewer male progenitors than female. Polygamous societies contributed to this phenomenon -- as did victorious armies in raping the widows of the defeated armies.
This phenomenon is also evident in the animal kingdom, such as the seal and big cat polygamous societies.
Post Script: A couple of people have reminded me that in previous generations there was a high death rate in childbirth. This meant that a man could have children by two or three wives over the course of his life, in a serial monogamy fashion.