We know what the birth of a revolution looks like: A student stands before a tank. A fruit seller sets

himself on fire. A line of monks link arms in a human chain. Crowds surge, soldiers fire, gusts of rage pull

down the monuments of tyrants, and maybe, sometimes, justice rises from the flames. But sometimes freedom and opportunity slip in through the back door, when a quieter subversion of the

status quo unleashes change that is just as revolutionary. This is the tantalizing idea for activists

concerned with poverty, with disease, with the rise of violent extremism: if you want to change the world,

invest in girls.

In recent years, more development aid than ever before has been directed at women — but that doesn't

mean it is reaching the girls who need it. Across much of the developing world, by the time she is 12, a

girl is tending house, cooking, cleaning. She eats what's left after the men and boys have eaten; she is

less likely to be vaccinated, to see a doctor, to attend school. "If only I can get educated, I will surely be

the President," a teenager in rural Malawi tells a researcher, but the odds are against her: Why educate a

daughter who will end up working for her in-laws rather than a son who will support you? In sub-Saharan

Africa, fewer than 1 in 5 girls make it to secondary school. Nearly half are married by the time they are 18;

1 in 7 across the developing world marries before she is 15. Then she gets pregnant. The leading cause

of death for girls 15 to 19 worldwide is not accident or violence or disease; it is complications from

pregnancy. Girls under 15 are up to five times as likely to die while having children than are women in

their 20s, and their babies are more likely to die as well.

Illustration by Gerard Dubois for TIME

There are countless reasons rescuing girls is the right thing to do. It's also the smart thing to do. Consider

the virtuous circle: An extra year of primary school boosts girls' eventual wages by 10% to 20%. An extra

year of secondary school adds 15% to 25%. Girls who stay in school for seven or more years typically

marry four years later and have two fewer children than girls who drop out. Fewer dependents per worker

allows for greater economic growth. And the World Food Programme has found that when girls and

women earn income, they reinvest 90% of it in their families. They buy books, medicine, bed nets. For

men, that figure is more like 30% to 40%. "Investment in girls' education may well be the highest-return

investment available in the developing world," Larry Summers wrote when he was chief economist at the

World Bank. Of such cycles are real revolutions born.

The benefits are so obvious, you have to wonder why we haven't paid attention. Less than 2¢ of every

development dollar goes to girls — and that is a victory compared with a few years ago, when it was

more like half a cent. Roughly 9 of 10 youth programs are aimed at boys. One reason for this is that when

it comes to lifting up girls, we don't know as much about how to do it. We have to start by listening to girls,

which much of the world is not culturally disposed to do. Development experts say the solutions need to

be holistic, providing access to safe spaces, schools and health clinics with programs designed specifically for girls' needs. Success depends on infrastructure, on making fuel and water more available

so girls don't have to spend as many as 15 hours a day fetching them. It requires enlisting whole

communities — mothers, fathers, teachers, religious leaders — in helping girls realize their potential

instead of seeing them as dispensable or, worse, as prey.

A more surprising army is being enlisted as well. A new initiative called Girl Up aims to mobilize 100,000

American girls to raise money and awareness to fight poverty, sexual violence and child marriage. "This

generation of 12-to-18-year-olds are all givers," says executive director Elizabeth Gore, the force of

nature behind the ingeniously simple Nothing but Nets campaign to fight malaria, about her new United

Nations Foundation enterprise. "They gave after Katrina. They gave after the tsunami and Haiti. More

than any earlier generation, they feel they know girls around the world."

And so the word goes out, by text, by tweet, on Facebook, that coming soon to a high school gym near

you may be a Girl Up pep rally, where kids can learn what it feels like to carry a jerrican of water for a long

distance, or how sending $5 to Malawi can stock a health clinic with girl-friendly materials or buy school

supplies. Or how $5 to Ethiopia can make the difference in a girl's not being married when she's 10. And

one at a time, a rising generation of American girls helps create the next generation of leaders, for the

coming quiet revolutions.