Call it the mommy penalty versus the daddy bonus.



A new government report finds that women with children under 18 earn less than women without minor children, while men with kids under 18 earn more than men without younger kids.

Experts say it’s further proof that, despite the many gains women have made in education and workplace equality in recent decades, moms are still at risk of earning less just because they also are parents.

“I think parenthood is like the new site of gender discrimination,” said Michelle Budig, a sociology professor at the University of Massachusetts at Amherst.

Budig’s research has shown that women generally make less money for each child they have, even after accounting for factors that would explain a salary reduction, like taking time off for child-rearing and career choice.

Men, on the other hand, are more likely to see an earnings boost for being married and having kids, also after accounting for other external factors that would impact earnings, according to Budig's research.

The Bureau of Labor Statistics report looked at the median — or midpoint — of weekly earnings for full-time workers. They found that in 2012 women with children under 18 had median weekly earnings of $680, while women without children under 18 had median weekly earnings of $697.

Meanwhile, men with kids under 18 had median weekly earnings of $946, compared with $799 for men without minor children.

Overall, the Bureau of Labor Statistics analysis showed that in 2012 women earned about 81 percent of what men earned in a usual week. That’s a much narrower gap than when the government started tracking the data in 1979, but the improvements have become much slower and less steady in the past decade or so.

The gap between men’s and women’s earnings exists at all age levels, but it is generally narrower when workers are young. Then, it widens more significantly starting around age 35, according to the latest BLS data.

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In 2012 women with children under 18 had median weekly earnings of $680, while women without children under 18 had median weekly earnings of $697. Getty Images stock

Experts say that widening gap could partly be explained by other factors, such as the fact that women are generally starting off with lower salaries and less lucrative careers, and find it harder to catch up over time. But many argue parenthood also is likely playing a role.

Of course, some moms are choosing to take less ambitious — and thus lower-paying — jobs because they don’t want to be away from home as much or they have more child-rearing responsibilities. But Francine Blau, an economics professor at Cornell University, said the problem happens when women who don’t want to make those trade-offs are nonetheless treated as if they will be less productive because they have children.



“If employers believe on average that women with children would be less good workers, then they might discriminate against all women with children,” she said.

Katherine Gallagher Robbins, a senior policy analyst with the National Women’s Law Center, noted research that has shown that, consciously or not, moms are often seen as less valuable workers. She points to a study in which participants were given two sets of résumés, with one set including activities that would point to being a parent.

The résumés that implied the woman was a mother generally got a lower competency and commitment rating, and a lower recommended salary, than the one for a woman who was not a mother. The résumés that implied a man was a dad, on the other hand, commanded a higher salary than the childless man.

Budig's research shows that the effect on earnings is true for all parents. But looking more narrowly just at white women, she found that the mommy penalty is especially strong for low-wage women, who Budig said are more likely to have trouble balancing less flexible jobs with the often unexpected demands of parenthood, like a sick kid.

“Women who earn less pay more — they pay a higher proportional penalty for kids,” she said.

Her research also has shown that married white moms pay a higher penalty than single moms after accounting for other factors, like age and the demographics of who gets married. But white women who are in the highest earnings bracket do not seem to be subject to the penalty.

In addition, her research found that the fatherhood bonus is especially true for white and Hispanic men who are well-educated.

Women are either the sole or primary breadwinner in 40 percent of U.S. households with children under age 18, in many cases because they are single mothers. That compares with just 11 percent in 1960. FeaturePics stock

“Men who conform to expectations of what makes a good man — being a highly educated married father — (are) more valued as an employee,” she said.

The data comes as moms are playing an increasingly important role in family finances. A Pew Research Center report released earlier this year found that women are either the sole or primary breadwinner in 40 percent of U.S. households with children under age 18, in many cases because they are single mothers. That compares with just 11 percent in 1960.

“It really is an economic concern not just for women but for their families in general,” Robbins said.

Blau, the economist, noted that families are changing in other ways too, and men are much more involved in their children’s lives than they were a generation ago. She said that shift in attitudes about home life could eventually lead to changing attitudes about the role parents play in the workplace.

As a practical matter, she also noted that more women are pursuing the type of education that is valuable to employers, such as law degrees and MBAs. That could spur employers to start thinking more about keeping these highly educated moms happy, loyal — and well-compensated.

“It’s sort of incumbent … upon employers to be concerned about these issues because they want to have the most productive workers,” she said.

Allison Linn is a reporter at CNBC. Follow her on Twitter @allisondlinn or send her an e-mail.