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What’s not to love about paternity leave? It helps a man to bond with his new-born, to strengthen his marriage, and catch up on sleep. So we’re left to wonder why the United States is a world laggard in offering paid leave to either a new mother or father.

Only 15 percent of American companies currently offer paid paternity leave, suggesting that our businesses see time off for new dads as a paid vacation with few beneficial consequences. Those who advocate for paternity leave resort to various kinds of appeals. Some invoke feminist values, noting that paternity leave encourages dads to share the workload at home. Others point out that men who take paternity lacontinue to be highly involved as their children grow older. In one study, University of Michigan researcher Norma Radin found that three-to-six year old sons of highly involved fathers ranked higher on tests of verbal intelligence. U.C. Berkeley psychologists Carolyn and Phil Cowan found that children with involved dads were better at classifying objects and placing things in logical order. And according to a study by psychologist Abraham Sagi, Israeli kids of attentive fathers showed more highly developed empathy. These effects last: In one study, children of highly involved fathers were still more self-directed than other kids 20 years later. And such sons grow to became better fathers themselves.

But in all of these discussions, we’ve forgotten—or given up on—the appeal to business. In fact, there’s something in it for the bottom line. Paternity leave enables families to survive in an increasingly unpredictable economy. It’s hard to know whose salary—his or hers—will be higher, and paternity leave helps parents become more domestically interchangeable. Just as companies “cross-train” workers to meet shifting market demands, so spouses need to cross-train at home.