The Three Myths of Cohabitation: Cohabitation has a notably deleterious impact on children. From the University of Virginia study, this fourth edition of the World Family Map project (an international study that tracks various indicators of family health) includes both some obvious and some surprising outcomes of cohabitation replacing marriage: kids who are born and raised by married parents are much more likely to flourish, and the least educated married families in Europe provide more stability for children than the most educated cohabiting families. See the full study at World Family Map 2017.