Andrea’s misplaced gratitude is not only common, but also an impediment to the elusive goal of equity in the home.

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The number of mothers in the labor force who have young children hit its peak and leveled off two decades ago. So, too, did the parenting contributions of men. For the past 20 years, research by the Bureau of Labor Statistics has consistently found that women employed outside of the home shoulder 65 percent of child-care responsibilities, and their male partners 35 percent.

Studies have also found that fathers who work long hours have wives who do more child care, while mothers who work long hours have husbands who sleep more and watch lots of television; that working mothers with preschool-age children are two and a half times as likely as fathers to get up in the middle of the night to tend to their kids; that men with babies spend twice as much weekend time engaged in leisure activity as their female partners do. Mothers remain more likely to miss work to tend to sick kids, to spend time with kids in the absence of another adult, and to maintain overall responsibility for managing the details of their children’s lives.

In 2017, the Organization for Economic Cooperation and Development called the uneven distribution of unpaid labor between men and women in the home one of the most important gender-equality issues of our time. And the problem isn’t going away; it afflicts even relatively young parents. “Millennial Men Aren’t the Dads They Thought They’d Be,” read a 2015 New York Times headline. MenCare, a fatherhood campaign working toward child-care parity in 45 nations, estimates that at the current rate of change, it will be another 75 years before women achieve gender equality in the home —a more optimistic figure than the 200 years the United Nations International Labour Organization predicted in March, on the eve of International Women’s Day.

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Reports of the modern, involved father have been greatly exaggerated. As the social psychologist Bernadette Park has put it, any change “is more in ‘the culture of fatherhood’ than in actual behavior.” The so-called marriage-between-equals discourse, ever present in certain corners of the country, bears little resemblance to what really goes on in the home. Even among couples who say they’ve achieved equal partnership, studies find that their mutual decisions tend to favor the needs and goals of the husband much more than the wife.

Still, many mothers, well schooled in the importance of sugar, spice, and everything nice, resist protest. They don’t give public voice to their sense of injustice. Instead, “when a dad comes” to a mommy-and-me class, “we clap,” reported Jay Miranda, a mother and blogger in Los Angeles.

Women’s gratitude is doubtless a result of the well-known, deeply felt fact that while domestic labor isn’t equal now, it was even less equal before. The 65/35 division is certainly better than the 80/20 women lived with in the 1970s and ’80s. One family-studies professor I spoke with told me that her mom is always telling her how lucky she is: “She’s comparing my husband to my father, who did nothing, but I’m comparing him to me, and I know I do way more!” Yet she said she “hit the jackpot” when she found her husband.