FORTUNE — Talk of global women’s rights always makes me think of Mr. Banks in the movie Mary Poppins. The British father puts up with Mrs. Banks marching through the foyer in her suffragette sash — as long as dinner is served punctually at 6 o’clock and no female folderol intrudes on men’s grave duties running an empire.

In today’s world of nuclear-armed tyrants and economic collapse, it is still hard to get the attention of world leaders on this softest of soft-power issues. But Secretary of State Hillary Clinton has at least figured out the right angle: The status of women, she argues, is linked to the economic fates of nations. Legal and cultural discrimination “is holding back economies,” Clinton told me during an onstage interview at the APEC CEO Summit in Honolulu, a gathering of business and government leaders from 21 Pacific Rim countries.

Clinton made the same case in private to a gathering of foreign ministers, as she has for more than a decade. Only now, because a growing body of evidence shows that female participation in economies boosts GDP, competitiveness, and productivity, she’s getting a serious hearing.

According to a Goldman Sachs report, narrowing the gender gap could lead to a 14% rise in per capita incomes by 2020 in several APEC economies, including China, Russia, the Philippines, Vietnam, and Korea. “It would increase the eurozone’s by 13% — and they need it,” Clinton adds.

Kathy Matsui, partner and co-head of Asia investment research at Goldman Sachs (GS), notes that the countries where the gender gap is widest — like Pakistan and Nigeria — have struggling economies. By contrast China — where women have relatively strong economic and educational standing — is enjoying a “growth dividend.” Japan’s growth, Matsui’s research found, has been impeded by women dropping out of the workforce.

50 Most Powerful Women in Business

In the developed world we have the luxury to bemoan the fact that only 12 of the Fortune Global 500 companies are led by women. In poor nations women often can’t inherit property or gain access to education or credit. Yet women are better savers, and — especially important in impoverished countries — they are more likely to spend their incomes on the health and education of their children, thereby raising a community’s economic status.

A number of major U.S. corporations are catching on to the fact that, as a McKinsey survey showed, it can be profitable to invest in women in developing countries. Goldman Sachs’s 10,000 Women campaign trains entrepreneurs worldwide. Coca-Cola (KO) has a similar program to support 5 million women entrepreneurs by 2020. Wal-Mart (WMT) has launched an initiative to double the amount of goods it purchases from woman-owned businesses globally.

American corporate managers are also looking to hire women for their overseas operations. “We want to tap into female talent before indigenous companies figure it out,” says John Rice, a GE (GE) vice chairman based in Hong Kong.

In 1995, as First Lady, Clinton gave a speech in Beijing proclaiming that women “will never gain full dignity until their human rights are respected and protected.” You need only see accounts of rape used as a weapon of war in the Congo or read Somaly Mam’s terrifying autobiographical account of sexual trafficking in Cambodia to understand those words still apply.

Money is power, though, and women are a labor resource, so Clinton’s decision, now as secretary of state, to make an economic rather than moral case for women’s rights seems shrewd. The argument certainly is gaining traction in parts of Asia, where self-made businesswomen are part of the millionaire class. Clinton can’t say whether her plea will resonate in countries such as Egypt and Libya, where women can only wonder if the Arab Spring will unleash their economic potential — or Islamic fundamentalism will crush it. But if any region can benefit from women in the workforce, it is the Middle East: Research shows that if women there are empowered, average household incomes could climb as much as 25%.

This article is from the December 12, 2011 issue of Fortune.

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