First, the Atlantic magazine announced “the end of men.” Then a Time cover story in March proclaimed that women are becoming “the richer sex.” Now a Pew Research Center report tells us that young women have become more likely than young men to say that a high-paying career is very important to them. Are we really in the midst of what Pew calls a “gender reversal?”

One stubborn fact of the labor market argues against the idea. That is the gender-hours gap, close cousin of the gender-wage gap. Most people have heard that full-time working American women earn only 77 cents for every dollar earned by men. Yet these numbers don’t take into account the actual number of hours worked. And it turns out that women work fewer hours than men…

The main reason that women spend less time at work than men—and that women are unlikely to be the richer sex—is obvious: children. Today, childless 20-something women do earn more than their male peers. But most are likely to cut back their hours after they have kids, giving men the hours, and income, advantage.