The gender pay gap is already a major social issue — but for moms in particular, the numbers are even more grim. This is the motherhood penalty, a term coined by sociologists to explain the systemic disadvantages faced by working moms in their careers, including the expansion of the already-troubling gender pay gap. These social scientists cite a number of causes for the motherhood penalty, most of them rooted in cultural perceptions of, and expectations placed on, working moms.

According to studies by the American Economic Review and the National Bureau of Economic Research, the gender pay gap widens significantly in women’s childbearing years, in the two decades after women join the workforce following college. But it’s not just an age thing: It’s a mom thing.

One Harvard study found that working mothers were typically recommended an almost eight percent lower starting salary than non-mothers, which is nearly nine percent lower than the recommended starting salary for fathers. Meanwhile, many men receive incentives in the workplace for having kids, enjoying wage bumps of up to six percent in some cases. What’s more, a 2017 working paper by the US Census Bureau concludes that among women who have their first child between age 25 and age 35, the gap between their salaries and their husbands’ doubles. For the remainder of their careers, that gap never fully closes.

One explanation for the motherhood penalty is that companies anticipate mothers’ absence during maternity leaves (which can be expensive for employers), caretaking, and other parental responsibilities, which sets an unfavorable perception of a working mom’s reliability. Bias also plays a role: Mothers are consistently perceived as at least 10 percent less competent and 12 percent less committed than non-mothers, which leads to lower starting salaries and fewer promotions.

Still, employer discrimination isn’t always 100 percent to blame for disparities in income and incentives for moms — there are a number of factors contributing to the gap. Maybe the biggest one is that the decade most critical to career-building, 25 to 35, is also the decade when most women have kids.

Mary Eschelbach Hansen, professor of economics at American University, says the types of jobs some women choose may affect gender pay gap statistics, along with the reality that some women with kids may have either less experience or more interruptions in their work history due to maternity leave or other parental responsibilities. Most companies see their employees as capital, which can depreciate over time if it’s not used.

“Experience, in some companies, is a very important part of one’s human capital. Put yourself in the shoes of an employer: You want to hire a woman, but there’s some probability that she might have an interrupted career, and that makes her less valuable,” Hansen tells Brit + Co. “When women drop out and try to come back, their skills and knowledge have depreciated. It’s hard to keep up if you’re not actually working, no matter what your job is.”

There’s some good news: In spite of evidence that the motherhood penalty does exist, women with kids aren’t automatically doomed to be punished with lower salaries. Countries with comprehensive, government-subsidized parental leave and childcare provisions for both mothers and fathers, like Sweden, boast significantly lower gender pay gaps than countries without. Unionized workplaces also help narrow the gender wage gap in general — including, specifically, for mothers, according to a 2016 study by Georgetown.

working mom and daughter

Additionally, different roles, industries, and companies have varying pay gaps, and it’s to a mother’s advantage to explore opportunities in environments where the gap may be smaller.

Where are the disparities in pay lower? Hansen says recent economic research shows that women who find work for “family-friendly” companies typically experience less wage penalty. When it comes to the motherhood wage gap, “family-friendly” is defined as a role that’s “easily substitutable” and an environment where people work together. Jobs in which employees are paid for performance are much more likely to have a wider pay gap.

“The gender pay gap is much smaller in sectors that don’t pay for performance—sectors where there are teams of people working, like education. Highly educated women and men who work in these family-friendly jobs are making virtually the same,” she says.

To explain the difference between a family-friendly job and a non-family-friendly job, Hansen used the example of a pharmacist — an industry where there’s virtually no pay gap thanks to industrial changes in how pharmacies operate. While, years ago, a pharmacist in a family-owned pharmacy would be remiss to find a replacement for her maternity leave — potentially leading to a larger pay gap — a pharmacist working for a larger company, like CVS, could be more easily replaced by colleagues with the same skills for maternity leave or other breaks.

On the other hand, in a competitive, commission-based sales job — roles without inherent flexibility — women with kids are bound to make less than males. Hansen says the highest gender pay gap is among the top-earning women in jobs where pay is focused on performance—the disparity is close to 40 percent when you get to the top one-percent of earners.

“This gap in these jobs would be much smaller if it weren’t for the motherhood penalty, which explains about one-third of the gender pay gap,” Hansen says.

While the gender pay gap and motherhood penalty are complex social problems with equally complex solutions, Hansen says a successful, lucrative career is still possible for women who want to be moms — though equality in salary is probably dependent on the industry and sector a woman ends up in. She encourages women thinking about having children to to consider pursuing training for a family-friendly job with lower gender pay gap.

“What would I advise my daughter? I would tell her to think about all the things she wants to have and how to balance them. And right now the best evidence shows that women can be very successful, just as successful as men, if they have one of these kinds of jobs — a job where you and other people work together and can fill in for each other. That’s the definition of a family-friendly job,” she says.

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(Photos via Getty)