Comment by helpfulmandrill

It seems to me like the effects of "normative" family structures might be different and better in countries that tolerate divorce. Where divorce is tolerated and non-stigmatised, those families that remain "normative" are, almost by definition, the most stable and healthy ones. If divorce were forbidden or stigmatized, then many more families would remain together where parents are always in conflict or where there is spousal abuse. So it is possible that the apparent benefits of normative family structures are only apparent in societies that tolerate "non-normative" family structures, and would disappear in less tolerant societies.