Social Inequality Leaves a Genetic Mark
In humans, the profound biological differences that exist between the sexes mean that a single male is physically capable of having far more children than is a single female. Women carry unborn children for nine months and often nurse them for several years prior to having additional children. Men, meanwhile, are able to procreate while investing far less time in the bearing and early rearing of each child.
So it is that, as measured by the contribution to the next generation, powerful men have the potential to have a far greater impact than powerful women, and we can see this in genetic data.