Washington (CNN) -- Toward the end of U.S. Secretary of State Hillary Clinton's surprise appearance at the TED Women conference Wednesday, she told the story of a girl and her father in a developing country.
"This teenage girl's father expected to force her into early marriage, but she had been to school and she received a cow, perhaps through the Heifer project, to encourage her to stay in school. When her father demanded she drop out of school and get married, she said no. When he insisted, she insisted right back.
"And finally she pulled out her trump card: 'If I leave and get married, I'm taking my cow, that cow belongs to me.' So guess what. She stayed in school, she was spared an early marriage, all because her father couldn't bear to part with the cow."
Clinton devoted her talk to the importance of empowering women and girls around the world, and the audience of 700 at the International Trade Center responded enthusiastically.
"Let women work and they drive economic growth across all sectors. Send a girl to school even just for one year and her income dramatically increases for life, and her children are more likely to survive and her family more likely to be healthier for years to come. Give women equal rights and entire nations are more stable and secure. Deny women equal rights and the instability of nations is almost certain."
Clinton said the goal of empowering women and girls is a "central tenet" of American foreign policy. "Women's equality is not just a moral issue, it's not just a humanitarian issue, it is not just a fairness issue," she said, "It is a security issue, it is a prosperity issue, and it is a peace issue.
"Therefore when I talk about why we need to integrate women's issues into discussions at the highest levels everywhere in the world, I'm not doing it just because I have a personal commitment or because President Obama cares about it. I'm doing it because it's in the vital interests of the United States of America."
Clinton said the status of women will be a key part of a new document the State Department is planning to release this week. Modeled on the Defense Department's review every four years of U.S. defenses, the "quadrennial diplomacy and development review" will assess American foreign policy.
Clinton spoke of an array of initiatives and programs the State Department is using, many involving technology that can empower women. Among them is a program in the wartorn Democratic Republic of Congo that enables women who are the victims of violence to record and transmit their testimony in criminal cases through the use of mobile phones.
Clinton's talk did not mention the ongoing worldwide controversy over the release of thousands of U.S. diplomatic cables by WikiLeaks. She did pay tribute to Elizabeth Edwards, who died the day before her talk.
"She lived with a fierce intelligence, a passion, a sense of purpose," Clinton said. "She would have appreciated this event, where we are coming together to look for solutions."
Clinton said the effort to empower women and girls faces cultural barriers: "The low value that many families and societies place on girls makes possible many of the worst abuses they suffer. But even among girls who are spared the worst, too often it is a girl who is still the first to drop out of school, the last to be fed, the last to receive medical care. And in too many places, she is taught there are special limits to what is possible for her.
"We need to reach out to faith leaders and community leaders to change the perception and treatment of girls, and to persuade men and boys to value their sisters and their daughters, their talents and their intrinsic worth."