The Gender Earnings Gap Persists Over a Lifetime

Sari Kerr sits at a panel presentation.

Many studies have shown that women earn less than men in the decade or so after they become parents. But what happens to women’s work, careers, and earnings as their children get older and the care responsibilities diminish? Sari Pekkala Kerr, senior research scientist at the Wellesley Centers for Women and leader of its Women in the Workplace Research Initiative, delved into this question with fellow economists Claudia Goldin of Harvard and Claudia Olivetti of Dartmouth.

In their recent paper for the National Bureau of Economic Research, they report that as children grow up and women work more hours, the “motherhood penalty” is greatly reduced, especially for those without college degrees. But fathers, in particular those who are college graduates, manage to expand their relative gains, and the parental gender gap in earnings remains substantial for everyone.

Kerr and her colleagues examined data from the National Longitudinal Survey of Youth 1979, which began in 1979 with around 13,000 14- to 22-year-old respondents who are now in their late 50s to mid-60s.

“Now that we can see how these folks’ pay has changed over time, we see that the story of the gender earnings gap is complex,” said Kerr. “It’s not so simple as ‘women have kids, work fewer hours, and make less money.’ There are differences in pay between women and men, between mothers and non-mothers, and between fathers and non-fathers that all play varying roles in the gender earnings gap.”

After they become mothers, women’s hours of paid work initially plummet—more so for college graduates. College-graduate mothers work fewer hours than non-mothers, but their hours increase as their youngest child begins elementary school and eventually graduates from secondary school. (Among non-college graduates, on the other hand, mothers and non-mothers work virtually identical hours.) Mothers increase their work time as their children grow up, but they still remain behind fathers.

How do these changing work effort patterns translate to pay gaps? The researchers separated the parental gender gap into these three components: the price of being female (the difference between men and women), the motherhood penalty (the difference between mothers and non-mothers), and the fatherhood premium (the difference between fathers and non-fathers).

“If you look at college graduate women and men at ages 35 to 39, women with children earn about 11% less than women without children—but the difference between mothers and fathers is about 42%,” said Kerr.What accounts for this enormous difference? It’s the fatherhood premium: the fact that not only do women earn less from their years of raising children, but men actually earn a premium when they have children.”

Though there is an extensive and long-standing body of literature regarding the fatherhood premium, it’s still not clear whether fathers earn more because they work harder after they have children, whether they become fathers when they are earning more, or whether supervisors tend to reward fathers more. Whatever the reasons, among different-sex couples men who become fathers can continue to advance in their careers because women disproportionately take care of the children. Mothers cut back on their paid work hours, work less demanding but more flexible jobs, and earn less.

Even women without children earn less than men with children. For men, having children and a wife who is their caregiver is related to their earnings boost. That fatherhood premium remains significant and increases with age, especially among college graduates.

To try to understand the persistence of the fatherhood premium, Kerr and her colleagues explored the possibility that the premium, and the fact that it increases with age, comes disproportionately from fathers who have time-intensive jobs when they start their families. Men who had time-intensive jobs before they had children were enabled or motivated to work even more hours when they became fathers than were men who were not fathers. Extra time spent at work when they were younger appears to have been disproportionately rewarded through career opportunities that produced higher earnings later. This would be true for many jobs in which early effort is required to make partner, obtain tenure, or achieve a promotion.

On the other hand, mothers who began their careers in time-intensive occupations were paid far worse than non-mothers in these occupations starting at age 40. One reason, according to the researchers, is that interruptions and lower hours at the start of employment are more heavily penalized in time-intensive jobs. The “mommy track” is well known to have a negative effect on the long-term career prospects of women in these occupations.

“It’s discouraging that having children gives men such an advantage that women can never catch up, no matter how many years of work experience they have,” said Kerr. “But the more we understand this problem, the more we can make efforts to mitigate it through government policies like paid leave and affordable child care, business practices that ensure equal pay and allow both men and women to attend to caregiving responsibilities, and changing cultural norms that distribute these responsibilities more equally. Closing the gender earnings gap will require action on all these fronts.”