“We are not designed, as a species, to raise children in nuclear families,” Christopher Ryan, one of the Sex at Dawn co-authors, told me over the telephone late last summer. Women who try to be “supermoms,” whether single or married, holding down a career and running a household simultaneously, are “swimming upstream.” Could we have a modernization of the Mosuo, Ryan mused, with several women and their children living together—perhaps in one of the nation’s many foreclosed and abandoned McMansions—bonding, sharing expenses, having a higher quality of life? “In every society where women have power—whether humans or primates—the key is female bonding,” he added.