Children "require a lot of work and a lot of resources," writes the economist Melissa S. Kearney. And "having two parents in the household generally means having more resources to devote to the task of raising a family." This includes working for pay, supervising kids, and much else.
That is the simplest argument for, as the title of Kearney’s book phrases it, a "two-parent privilege": an advantage to growing up in an intact family. The privilege is denied to a large number of American children, disproportionately those who already face other disadvantages. As of 2019, 84 percent of kids whose moms had four years of college, but only 60 percent of kids whose moms had a high school degree or some college, lived with married parents. The racial gaps are even starker: Even among kids whose moms have a high-school education or less, about two-thirds of white kids, but only about one-third of black kids, have married parents.
Kearney lays out the evidence that having a second parent around is good for kids and offers suggestions as to what might be done, with the endnotes commencing before page 200. The Two-Parent Privilege is impressively concise and well-argued, yet sure to start as many debates as it ends, regarding both the damage done by single parenthood and what policy reforms are in order.
Given how obvious it is that "2 > 1"—the title of a key chapter—why insist on detailed evidence?
One reason is that many Americans, including well-educated Americans who value the stability of their own nuclear families, wince at the thought of talking about the consequences of single parenthood: It feels too judgy and puritan. Kearney writes that when she brought up family structure at an economics conference focused on inequality, the "muted reaction" consisted of "uncomfortable shifting in seats and facial expressions that conveyed reservations with this line of inquiry." A forceful argument helps to break through that reticence.
Another reason is that, scientifically, it’s extremely difficult to assess the consequences of single parenthood. Kids of single parents unquestionably do worse than kids of married parents across countless measures, but single parenthood does not occur under experimental conditions. Single-parent families differ from married ones socioeconomically—and are usually created through parents' choices, whether well-considered (such as leaving a bad partner who would make a child’s life worse) or not (such as inconsistent use of birth control). If we somehow induced single parents to raise their kids within marriage, there would still be big differences between them and the parents who marry before getting pregnant and stay together without prompting.
And finally, though Kearney does not engage with it, decades of research from the field of behavioral genetics shows that genes are far more powerful in explaining how kids turn out in adulthood than the home environment is; indeed, sometimes the home environment seems to exert no measurable influence at all. There are key exceptions, such as educational attainment, to this general pattern, and of course giving kids a better environment during the time they grow up is a good thing in and of itself. But we should at least be open to the idea that, so long as kids are cared for on a basic level, such improvements may have only modest effects on long-term outcomes.
So, does Kearney have the goods to overcome both politeness and scientific obstacles? In that crucial "2 > 1" chapter, she cites some compelling studies, though there remains considerable uncertainty here.
As Kearney notes, researchers have used a few different tricks to figure out the real effect of family structure. For instance, parental divorces give researchers the chance to see if individual kids’ outcomes change for the worse after a parent leaves, as well as to see if younger siblings, who spend more time being raised by a single parent, see worse effects. Researchers can also statistically control for obvious differences across families, such as parental race and education levels, though it’s never possible to include every variable that might matter. Or they can look at policy changes that affected family structure, such as the growth of no-fault divorce laws, to see if kids’ outcomes changed when the laws did.
Even the most rigorous studies often find bad effects, as Kearney documents, though she tends to focus on the negative direction of the effects without discussing their precise magnitude, which would be key to quantifying the benefits of restoring two-parent families. And nuances abound. A major 2013 review Kearney briefly mentions, for example, noted that more careful studies tend to produce smaller results than simpler comparisons between single- and married-parent families. Others have pointed out that, even among these better studies, about half produce statistically insignificant results.
On balance, it’s fair to say that stable two-parent families are good for kids—2 > 1 is powerful common sense, and there’s a lot of research consistent with it. But it remains hard to say exactly how much kids' outcomes would improve if we somehow increased marriage among those not currently inclined toward it.
And how would we go about doing that? If 2 > 1 is an obvious inequality, 1 + 1 = 2 is a difficult equation.
It’s not like we’re heading back to 1950—pressuring pregnant couples into shotgun marriages, making divorce more difficult, shoving women back out of the workforce, cutting welfare benefits for unmarried mothers, etc.—and Kearney doesn’t want to anyhow. She proposes several other ideas.
It’s somewhat telling that her first idea is to foster a "norm" of two-parent families. Norms are important, but they’re also a standard cop-out in the later chapters of books about social problems: How about everyone just changes their attitudes and behavior so we don’t have this issue anymore?
The next idea is boosting the "economic position" of men with no college degree, a promising but also tricky proposition. There’s good evidence connecting the decline of marriage among the less-educated to the erosion of men’s economic advantage and "marriageability," but that process won’t necessarily play out in reverse. The recent fracking boom instead seems to have simply increased fertility, among the married and unmarried alike, for instance, according to Kearney’s research.
Further, the fact that men still outearn women, even among those without a college degree, complicates the matter—to focus on boosting the economic position of less-educated men is to advance the sex that’s already ahead in the labor market, which is sure to perplex feminists. Speaking of whom, Kearney reassures readers that despite her concern for less-educated men’s "relative economic position," she sees the "growth in women’s earnings and economic opportunities" as a "positive social trend." In the end, her concrete ideas for helping men include education and criminal-justice reform, apprenticeship programs, and (presumably gender-neutral?) wage subsidies.
Then she proposes government programs to promote two-parent involvement even among couples who are no longer together, fund mentoring programs, and provide general public support for poorer families. Kearney rejects the idea that welfare benefits drove the increase in single motherhood—the trends certainly line up, but more rigorous research struggles to nail down the connection—and cites studies finding that government aid improves kids’ outcomes. She does, however, briefly note that some government policies contain marriage penalties, and supports removing them.
That’s all basically fine, but I doubt it’s up to the task of restoring two-parent families. Maybe nothing is, short of aggressive subsidies given to married parents but not unmarried ones. Over the past half-century, it has become both more feasible financially, and more acceptable socially, to create a single-parent household—and the underlying phenomena of economic growth, technological improvement, and social liberalism seem unlikely to end. Reforms like Kearney’s can produce some results, but in all likelihood, the rise of single parenthood is something America will be coping with, not reversing. Kearney, nonetheless, deserves great respect for saying out loud an awkward truth.
The Two-Parent Privilege: How Americans Stopped Getting Married and Started Falling Behind
by Melissa S. Kearney
University of Chicago Press, 240 pp., $25
Robert VerBruggen is a fellow at the Manhattan Institute.