How motherhood widens the gender pay gap

When it comes to the gender pay gap, the greatest inequality may be on the home front. The pay difference is higher between married men with children and married women with children than for any other demographic, according to a new study from compensation research firm Payscale.

That backs up previous studies that have found women take a "motherhood penalty" when they have children, such as research from sociology professor Michelle Budig at the University of Massachusetts, Amherst. Budig has found that men's earnings bump up when they have kids, while women's slipped 4 percent for each child they have.

While it's not clear what causes that gender gap between parents, Payscale senior editorial director Lydia Frank noted that preconceptions about gender roles can show up in pay.

"It's a little bit tough because we have the data showing that gap, but what we don't have is the why," Frank noted. Still, she said she believes cultural expectations play a role in how men and women are treated in the workplace.

"If you ask somebody outright how they feel about it, they might take the time to think about it and not necessarily assume that a woman will start neglecting her work duties because they have kids and that men will be fine because they have a wife at home," said Frank. "But a lot of people do hold those beliefs to be true. It's that idea of unconscious bias."

That bias has been tracked in how Americans feel about working mothers. One-third of respondents in a Pew Research Center poll said they believe young children are best off with a mother who doesn't work at all.

Yet Payscale found that men are actually prioritizing family obligations more than women workers, which turns some of that bias about working moms on its head. About 52 percent of men say they prioritize home and family commitments over work at least one or two times a month, compared with only 46 percent of women, the company's survey found. The company's findings are based on about 1.4 million full-time workers who took a Payscale survey between July 2013 to July 2015.

"Men tend to be not as forthcoming with employers when they are doing that," Frank said. "They are telling us honestly that they are prioritizing family over work more often because it's anonymous, but they may be telling their employer they're going to the dentist."

In addition to cultural stereotypes, men are more likely to ask for raises more often than women, which can lead to bigger differences in pay as workers progress in the careers.

The motherhood penalty, as well as differences in how the genders negotiate pay, could also explain why women's earnings tend to peak earlier in their lives than men's. Women's salaries max out between the ages of 35 to 40, reaching a median of $49,000. Men's salaries tend to rise until they reach 50 to 55, at a median of $75,0000, Payscale found.

The gender pay gap is pervasive across every industry. Payscale found none in which women earn as much as or more than men. Still, some industries have worse gender pay gap than others, such as the mining, quarrying, and oil and gas industry, where women make 5.4 percent less than men, once the data is controlled for factors other than gender, such as education and skills. That's the biggest controlled pay gap in the survey.

When pay isn't controlled for those other factors, the gap is much larger. By that basis, women in the mining, quarry, and oil and gas industries earn 25 percent less than men.

Women are getting the sense that it's tougher to get ahead once they have families, according to a research report issued by the Pew Research Center this week. About 41 percent of women said being a parent made it harder to advance in the workplace, compared with 20 percent of working dads.

But the issue of care -- whether for children or elderly parents -- isn't only a women's issue, Frank added.

"Employers have to support the fact that employees have people in their lives they have to take care of," she said. "Traditionally those duties have fallen to women, so this has become a women's issue because of where those responsibilities for care have fallen. But as things have shifted and we're balancing those responsibilities, it'll be less of a woman's issue and more of a worker's issue."