Over the course of researching my book Can’t Even: How the Millennials Became the Burnout Generation, I spent weeks wallowing in the economic history that shaped boomers, days immersed in child-rearing philosophies of the 80s, so much time thinking through how the attitudes of consultants and bankers trickled down to define our understanding of “good work” as “more work.” There were a lot of stats that have clung to me, particularly concerning the overarching idea that we as millennials will be the first generation since World War II to take a step back—not just in terms of health and life expectancy but also wealth accumulation—from our parents.

None of the statistics I encountered were, in truth, that shocking. I knew how much student debt we’ve taken on; I knew how much less time we devote to leisure; I knew just how precarious the millennial experience has become. But one statistic surprised me, and has clung to me ever since I first encountered it: during the last 40 years, women with jobs have spent just as much time parenting as stay-at-home mothers did in the 1970s.

“Parenting” is a loose term here, but it describes time in which parents are in direct supervision of their children. Feeding them, playing with them, taking them to the park—the list goes on. So read that stat again: even when mothers leave home to work during the week, they’re still spending just as much time with their children as stay-at-home mothers did back in the 1970s. That is wild.

During the last 40 years, women with jobs have spent just as much time parenting as stay-at-home mothers did in the 1970s.

The “second shift,” a term popularized in 1989 by the sociologist Arlie Russell Hochschild, isn’t a metaphor: mothers today are putting in a full day at work, and then they’re putting in an additional full day of active parenting. And the only way that can feasibly work for most mothers is by allocating very, very little time for themselves, whether for hobbies, sleep, or socializing. Mothers go out to brunch—with their children in tow. Mothers go on runs—with their children biking beside them.

That’s the expectation of the bourgeois mother: somehow be working all the time but also be parenting all the time. Anything less and you’re failing at (bourgeois) motherhood. I heard about a mom the other day who, when she’s on Zoom calls with her friends, deflects all requests from her kids. “I’m not parenting right now,” she says. That sort of disciplined maintenance of parenting and non-parenting spaces flies in the face of everything that millennial women have internalized about themselves: that they should be all things, to all people, at all times. But it’s a profound act of care, too, for basically everyone involved. Children learn to figure out things by themselves—or, depending on the situation, there can be multiple “primary” parents. And the parent gets a space, however brief, to just be one thing.

Anne Helen Petersen’s Can’t Even: How Millennials Became the Burnout Generation is out now from Houghton Mifflin Harcourt