In a widely read piece for The Atlantic, Princeton professor and soon-to-be-president of the New America Foundation Anne-Marie Slaughter asked “Why Women Still Can’t Have It All.” One answer: because men are doing less and less of it.

According to a report released May 29 by the Pew Research Center, a record number of women are primary wage earners for their families. Fully four out of ten households with children under 18 are headed by meal-ticket-moms, up from one out of ten in 1960.

Superficially, this is a cause for celebration. As America embraces egalitarian social norms, women are on increasingly equal (though still imperfect) footing with men in the workplace. Women comprise nearly half the labor force, and nearly two-thirds of women with children are employed. Reified gender roles are becoming more pliable. Glass ceilings are becoming retractable roofs.

When we talk of these superstar moms, we tend to think of highly educated, high-earning career professionals. We marvel at their ability to juggle the responsibilities of motherhood with the relentless—and often ruthless—challenges of the white-collar workplace. We wonder if their absence from the home will hurt their children’s development. We rightly discuss policies that can make the work-life tradeoff less onerous.

By one measure, the benefits of professional moms are clear: their families are economically advantaged. Two wage earners are better than one. And the data shows female-dominant households are best of all. Married mothers who earn more than their husbands head families with median incomes of $80,000—considerably greater than the national median of $57,100 for all families with children, and $2,000 more than families where the man is the primary wage earner.

Problem is, these rosy statistics obscure the main reason mothers are at the fore: America’s epidemic of single motherhood.

A quarter of American children—some 18 million—live in single-mom-headed households, up from just 8 percent in 1960. And 41 percent of all births are to single mothers. That’s right—amost half of American kids born today will grow up with dad absent from day one.

Unlike their wealthier counterparts, for whom careers are a lifestyle choice, single moms work out of necessity. Nearly a third of single-mom-headed families are poor—six times the poverty rate among married families. Half of children under 18 raised by single moms are poor, compared with 11 percent of children in married households. Seven out of ten children in deep poverty (under 50 percent of the poverty line)—4.7 million—grow up without a father.

Even among single-mom headed households where the mother works full-time year-round, 13.4 percent of children are poor. In 2011, the median income for a single-mom-headed household was $25,000—less than a third of the $79,000 median among households with married parents.

Compared with married mothers, single moms are younger, less educated, and more likely to be minority. A third of single moms are teens. A third have children by multiple partners. Four-fifths are minority. Nearly half lack a high school degree, and 84 percent have no college experience.

Worse still, while the current unemployment rate among women (7.3 percent) is better than that among men (7.7 percent), the unemployment rate among never married women is considerably higher, at 11.8 percent. The women most desperately in need of jobs are those least likely to have them.

Indeed, there are fewer surefire ways to become poor than being a single mom. In reality, of course, the causality runs both ways. Single-parent-headed households have fewer resources and more demands—and are therefore more likely to be poor; but at the same time, growing up in poverty makes single motherhood more likely, through diminished future expectations, fewer opportunities for personal fulfillment, and inadequate information about contraception. In poor communities, women are less likely to find suitable partners—and once they have an out-of-wedlock births, their chances at marriage are reduced.

Breadwinners? Maybe. But bread is about all they’re winning. A better description of these heroic single moms may be “role-losers”—women forced to perform double-duty because the men in their lives cannot or will not.

Sadly, the biggest losers are the children themselves.

Children who grow up poor are likely to remain poor. Compared with other developed countries, the United States ranks near the bottom in economic mobility. According to the Brookings/Pew Economic Mobility Project, fully 43 percent of Americans born into the lowest income quintile remain there as adults; 70 percent fail to reach the middle quintile.

In no small part, it’s because poverty compromises parenting. Higher levels of stress, combined with inexperience, labor market constraints, and lack of social supports, puts poor single moms at a profound disadvantage. The urgency of living day-to-day undermines planning and distracts from child-rearing.

Precisely when kids need good parenting most—in their early years—they are least likely to get it. Research in neuroscience and child development has established the supreme importance of early childhood for lifelong well-being. Investing in children is not unlike investing in retirement accounts: missed opportunities early on can be made up only at great effort and expense, if they can be made up at all. Nature and nurture interact to structure development—but it is parents who determine both. Not surprisingly, socioeconomic status is predictive of academic achievement, and educational attainment is the key determinant of future earnings.

Headlines about breadwinning moms and debates about evolving gender roles rightly have a place in the national discourse. But at the same time we must remember the challenges of career moms pale in comparison to the plight of single moms and their children.

A good place to start is with promoting responsible fatherhood. President Obama has championed his Fatherhood and Mentoring Initiative, and child support enforcement agencies around the country collect some $27 billion a year in payments.

Yet, federal funding for fatherhood programs remains scarce. Two of the Administration’s core programs—the Responsible Fatherhood Program and the Healthy Marriage Program—are jointly funded at just $150 million annually. Although additional funds are available through such avenues as TANF and the Social Services Block Grant—and while local government agencies and nonprofits often pioneer innovative services to fill the gap—the United States generally lacks a comprehensive approach to address one of the primary causes of modern-day American poverty: declining rates of marriage and increasing rates of male absenteeism. Just 63 percent of family with children are headed by married partners, down from 87 percent in 1970. Among African-Americans, the story is even bleaker: marriage rates among black families with children is just 35 percent.

The Pew report highlights an important trend. But the real story isn’t that women are doing more—it’s that men are doing less. With Father’s Day right around the corner, it’s time we as a nation start talking about how dads can step up to the plate.