Moms' Employment After the Kids Grow Up

There’s been a lot of debate over how much money women earn relative to men—and why. As I noted last year in my review of the economist Claudia Goldin’s Career and Family, the gap is mostly not attributable to discrimination by employers, and only about a third of it is explained by the fact that women cluster in somewhat lower-paid occupations. The biggest culprit, instead, is children: when a baby arrives, it’s usually the mother who scales back her paid work to dedicate more time to child care and other work in the home.

But what happens in the decades that follow, as kids slowly become more self-sufficient and eventually move out? That’s the focus of an illuminating new study from Goldin and two coauthors. The conclusion is that older moms regain most of the ground they lost to women without kids, but they do not close the gap with fathers.

The study is based on the 1979 National Longitudinal Survey of Youth, which began following a group of Americans in their teens and early 20s and continues to collect new data from them to this day. By tracking these individuals’ work lives from their 20s to their 50s, Goldin et al. can measure how gender gaps evolve over, and they can take account of how specific individuals differed even before they had kids (so that the results aren’t thrown off by certain types of people “self-selecting” into parenthood or childlessness).¹

The researchers focus specifically on the gap between parents from the two sexes—mothers and fathers—which can be broken down into three components: the “motherhood penalty,” or the extent to which women with kids earn less than they likely would have without kids; the “fatherhood premium,” or the extent to which fathers earn more than they would have otherwise; and the remaining gender gap, which the authors term the “price of being female.” They also show how time spent working and occupational choices affect these numbers.

Since it’s already well-known that mothers’ careers take a hit when kids arrive, the most interesting aspects of these analyses have to do with the recovery in women’s work years later. For instance, per the authors’ calculations and simulations, college-grad moms in their late 20s and early 30s work about 7 hours per week less than comparable non-mothers (4 hours for non-college-grads), but the gap falls to less than 2 hours for these moms in their late 50s (and the gap vanishes entirely for non-college-grads).

When mothers are compared instead with fathers, though, the increase in work is less pronounced. Roughly speaking, the gap starts at 10 hours and is cut in half for college grads, and it starts at eight hours and is cut by a quarter for non-grads.

Similar pictures emerge with overall earnings, which fall by roughly a quarter for new moms. Over time, moms mostly catch up to childless women—especially for non-college-grads, and even more when controlling for hours worked and experience in the labor force—but not to dads. Much of the difference is the much-studied overall gender gap (and would likely fall with additional controls, such as for occupation). But a healthy chunk of it² is the “fatherhood premium.”

So, what on earth is going on with that? Bluntly, men earn more when they have kids, at least in part because they work longer hours—and dads especially pull away from other workers in occupations that lavishly reward employees who work long hours. As Goldin et al. remark, splitting their analysis in two based on the time intensity of the jobs these folks held early in their careers, “men who had time-intensive occupations when younger were enabled or motivated to work even harder when they had children than were men who were not fathers.” As for why this is the case, having kids in itself “may motivate them,” and wives who stay home or work part time “may further enable fathers to focus on their careers (by easing time constraints or offering advice and motivation).”

Naturally, the next question is what, if anything, to do about all this. As I discussed in my review of her book, Goldin is a strong supporter of equalizing the work and child-care burdens shouldered by men and women, both in society at large and within individual couples (what she calls “couple equity”). The more libertarian-minded might simply say that if free men and women are making their own work-family decisions, rather than being forced into suboptimal arrangements by discrimination or sexist laws, they should be left alone. Either way, it helps to start with a clear picture of how mothers and fathers fare in the labor force, and this new study is an invaluable contribution to that discussion

Robert VerBruggen is an IFS research fellow and a fellow at the Manhattan Institute.

1. More technically speaking, they use “individual fixed effects” in many of the regressions.

2. The precise numbers are expressed in log earnings and thus are a bit tricky, but for 55-59 year old college grads, even in a model that controls for “log(hours), log(weeks), previous five year’s work experience, and advanced degrees (for the college graduate sample),” the overall parental gender gap in earnings is -0.603 (or a whopping 60 “log points”): a motherhood penalty of -0.068, a “price of being female” of -0.300; and a fatherhood premium of 0.235. For non-grads in the same age range, the corresponding numbers are -0.435 (for the overall gap), -0.029, -0.276, and 0.130.