On Equal Pay Day, Here's a Reminder That Moms Are Screwed Over Most by the Gender Wage Gap

April 12 is Equal Pay Day, which means it's time for an annual reminder the gender wage gap is still alive and well — and it doesn't just screw over women. That said, it's true that the income disparity between the sexes does hurt women the most — especially if they have kids.

Given the income gap is all about inequality, it should come as no shock that the gap in earnings affects people unequally: Working mothers, who numbered 31 million in the United States in 2012, have the largest wage gap of any demographic, whether they're married with children or on their own. 

The disparity is the biggest for married moms, who earn 31% less on average than married dads, according to a study by PayScale. The gap is slightly better for women who are married without children (they make just under 21% less than men who are married without kids) and significantly smaller for childless single women.

The disparity within the disparity indicates the wage gap likely isn't tied to gender alone, but is rather affected by what sociologist Michelle Budig identified as the "motherhood penalty": Married women with kids don't just make less on average than their male counterparts, but also less than women who do not have kids. 

That doesn't negate the fact that there's still a chasm between men's and women's earnings that's tied to gender alone. A study by the American Association of University Women found young female graduates who don't have children still make 18% less than men right out of college; while women might make more during their 20s, their wages start to stagnate pretty much as soon as they turn 30. 

Some speculate the pre-kids gap is due is an unconscious assumption that women will inevitably have children once they get older (of course, many do), and therefore require more flexible schedules and time off from work. Thus, the logic goes, they'll be less dedicated to their jobs. 

By contrast, when men have kids it actually tends to boost their earnings: What is a motherhood penalty for women becomes a fatherhood bonus for men, with fathers making approximately 6% more after starting families, the New York Times reported. Mothers, on the contrary, can expect to earn about 4% less with every child they have. 

As is typically the case, the situation is even worse for moms who don't have partners, an estimated two-thirds of whom work. Single parents generally have a significantly harder time affording basic expenses; for single mothers, that's compounded by the fact that they make considerably less than their married counterparts, a 2013 Pew Research Center analysis found. (Moms who made more than their husbands made a median of $80,000 in 2011, while single moms made $23,000 median.)

Many are minimum wage earners: Nearly 6 in 10 minimum wage workers are women, and about one-third have kids. Add to that the fact that a massive number are also women of color, who are disproportionately negatively affected by the gender wage gap, and our society starts to seem remarkably fair and equitable! Just kidding — it's an unequal embarrassment.

There are plenty of explanations for why working mothers get the short end of the stick (or the checkbook), but no explanations are excuses. Measures like the Paycheck Fairness Act could be a huge boon for all women's wages. But working women trying to support families (i.e. an ever-growing number of workers in the U.S.) could also benefit from changes like more flexible parental leave policies, a higher minimum wage and affordable daycare. 

Enforcing such policies could be good for everyone; everyone wins when fewer people get screwed overall.