Why the Great Crossover Matters

Americans often think of decisions about when—or whether—to marry and when—or whether—to have children as deeply private, nobody’s business but the individuals involved. But this thinking ignores just how much these choices are beset by what economists call negative externalities. That is, they are personal decisions with costs that affect everyone. When one couple in their early twenties has a child well before they commit to raising him together over the long haul, the external effects are easily absorbed. But when millions of young couples make that same choice, the costs grow exponentially. The personal becomes societal. The Great Crossover, in other words, is America’s problem.

Researchers now view family instability as one of the greatest risks to children’s well-being. Yet unmarried adults, including single twentysomethings who make up about half of unmarried parents, are by definition unsettled. Whether they have children or not, single young adults are understandably interested in finding new romantic partners. They are often successful in doing so, as Figure 19a indicates. Cohabiting couples who have a child in their twenties and then break up—and that’s almost two-fifths of them in the first five years—often also go on to have another partner or partners.44 One study of young urban parents based on data from the Fragile Families and Child Wellbeing Study found that for 59 percent of unmarried couples with a baby, at least one partner already had a child from a previous relationship. This was the case for just 21 percent of married couples in urban America.45 These children have to find their way through a muddle of relationships with stepparents, step-grandparents, stepsiblings, and half siblings, even while—as is so often the case—sacrificing a close bond with their own fathers. It’s true that many children are successful at navigating their way through these relationships; but many others pay academic, psychological, and financial costs for their entire lives.


Most researchers agree that on average, whether because of instability or absent fathers or both, children of unmarried mothers have poorer outcomes than children growing up with their married parents. They suffer more school failure, behavioral problems, drug use, and a greater likelihood of becoming single parents themselves.46 And while many people assume that the children of cohabiting parents will enjoy the same stability and father time as the children of married parents, that is often not the case in the long run. Cohabitation in the United States is far more unstable, conflicted, and short-lived—and far more frequently associated with child abuse—than marital relationships.47 As Figure 19b indicates, cohabiting men and women who have a child in their twenties are three times more likely to break up before their child’s fifth birthday than are married couples.

At the macro level, the Great Crossover is connected to some of our biggest domestic and economic problems. It’s part of a sad, ironic cycle, both a response to and a generator of the economic and social troubles now enveloping Middle America. Young couples with children may defer or steer clear of marriage because a parent does not have a steady, decent paying job. But unmarried couples break up more often, leaving more mothers raising children alone, which generally increases their odds of poverty.48

The Great Crossover, in other words, creates its own negative economic and cultural feedback loop, and this feedback loop is no longer limited to the most disadvantaged in our society. The Great Crossover also reinforces America’s low levels of economic mobility. Because children born to stable, married, college-educated parents are more likely to graduate high school, go to college, and graduate college, they are better equipped to thrive in a knowledge economy. Children from less-educated homes marked by instability and fatherlessness (which, as we’ve seen, is increasingly the case) have less success in school starting at the youngest ages and a lower likelihood of attending, much less graduating from, college. Without higher education, their chances of moving up the income ladder are stunted.49 As we’ve seen, men without a college degree are often deemed “unmarriageable,” which leads in turn to another generation of unmarried parents. The Great Crossover, in other words, creates its own negative economic and cultural feedback loop, and this feedback loop is no longer limited to the most disadvantaged in our society.

44 See Sharon H. Bzostek, Sara S. McLanahan, and Marcia J. Carlson, “Mothers’ Repartnering after a Nonmarital Birth,” Social Forces 90 (2012): 817–841.
45 See Bendheim-Thoman Center for Research on Child Wellbeing (Princeton University) and Social Indicators Survey Center (Columbia University), “The Prevalence and Correlates of Multipartnered Fertility among Urban U.S. Parents,” Fragile Families research brief 35 (April 2006), www.fragilefamilies.princeton.edu/briefs/ResearchBrief35.pdf.
46 See, for instance, Amato, “Impact of Family Formation Change.”
47 See Cherlin, The Marriage-Go-Round; W. Bradford Wilcox et al., Why Marriage Matters, Third Edition: Thirty Conclusions from the Social Sciences (New York: Institute for American Values, 2011).
48 Indeed, research by economists Adam Thomas and Isabel Sawhill suggests that recent increases in single parenthood have played an important role in driving up child poverty in the United States. See Adam Thomas and Isabel Sawhill, “For Love and Money? The Impact of Family Structure on Family Income,” Future of Children 15 (Fall 2005): 57–74.
49 See Wilcox et al., Why Marriage Matters; Ron Haskins and Isabel V. Sawhill, Creating an Opportunity Society (Washington, DC: Brookings Institution, 2009).