The life-work dilemma for women has long been that “the workplace has changed in their favor, but home hasn’t,” she says. Men, however, “have the opposite problem. More is expected of them at home, but expectations have not shifted at work.” Which explains why the percentage of fathers in dual-income households who say they suffer work-family conflict has risen to 59 percent from 35 percent since 1977.

Younger couples say they want and expect parity in their relationships. But many women still carry a chip on their shoulders, chiseled in part by years of keeping all those to-do lists in their heads. And if men can find no relief from the pressures of work, they are not going to be able to fit into the revamped economy of home.

How then to inch toward change? Can we make it “manly” (or even better, “gender neutral”) to spend a day with a child, or earn less money but have more family time, or be the only parent at a parent-teacher conference because your wife has a meeting? “If long hours are really about proving ‘whose is bigger,’ you can have flex policies until the sun sets and men won’t use them,” Williams says.

Indeed, where flex policies are offered, American men don’t use them as much as American women do. In California, one of two states in the country to provide paid parental leave (or “bonding leave”) for both parents, 74 percent of new mothers took the new benefit compared with 26 percent of new fathers. This is, to be sure, an improvement over the 17 percent who took it when the program was first introduced in 2004-2005. (It is also significantly higher than the percentage of French men who take time off. French law allows both parents to take a leave or to work reduced hours until their child is 3, but 97 percent of those who do so are women.) It’s better than it used to be, but it’s far from equal.

There are some practical reasons for these discrepancies. Biology dictates that many women will take pauses during the prime career-building years that men don’t need to take. Similarly, breast-feeding during the first month to year of life means a child necessarily spends more time with the mother. Often, though, what look like causes are really effects — we make assumptions about sex roles and then reinforce them with our behavior. If you challenge those assumptions, it follows that you can change behavior. Which explains what happened in Sweden.