There’s only one problem with Abe’s plan: It’s targeting the wrong people. More maternity leave might sound like a great idea, but as long as mothers are the only parents taking leave, longer stints at home actually worsen job discrimination against them and makes them less likely to pursue a career.

Rather, as the experiences of Sweden, Iceland, and a handful of other countries show, the secret to keeping mothers in the workforce lies not in giving them more time off, but in getting more fathers to stay at home instead. And that, it turns out, depends to a large extent on getting rid of the pay gap that exists between men and women almost everywhere.

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There are lots of good arguments for adding more women to the workforce. An economy grows when it adds more people to make things, or when the workers it has make things faster. Since upping productivity—as the latter option is called—is notoriously tricky, when an economy is stagnating it’s generally a good idea to scare up some new workers. Importing immigrants is one choice (that’s what the US.. favors). The other is simply getting more of your working-age population into jobs. And in most developed countries, the biggest base of unemployed workers is women.

The benefits of upping the share of women working come in fits and starts. At first, productivity tends to decrease, partly because some of this additional female labor is usually part-time, and partly because new people need training.

Over time, however, influxes of women make a workforce not just bigger but also more productive. Firms in the top quartile for female senior managers earn 56 percent more than companies with none, according to McKinsey & Company. This may be because management teams with an equal gender balance tend to innovate more, make more informed decisions, and take fewer big risks. The share prices of companies with one or more women on the board outperform those with none, Credit Suisse research shows. Although that’s not a causal relationship, Credit Suisse cites research suggesting that greater gender diversity in leadership improves communication and reduces corrosive competition among senior managers.

There are other benefits to the economy too. Accounting for seven-tenths of global consumer spending, women are “the ultimate agents of aggregate demand,” says Christine Lagarde, head of the International Monetary Fund. Companies that design and market their goods and services in ways that appeal to women will sell more effectively than those that don’t. Companies led by talented women are more likely to pull that off.

Women also tend to spend more on healthcare and education. These services are more labor-intensive than most sectors, so they generate more jobs. And when these “agents of aggregate demand” earn more, they’ll spend more too.