The World's Greatest Return on Investment

My mom is from Argentina, and we often spent Christmas holidays there while I was growing up. When I was 12, I was riding on a train with my parents to spend Christmas Eve with family friends living outside of Buenos Aires. The mood on the train was festive -- everyone was dressed up and many carried holiday gifts. At a station about 20 minutes outside the city, I saw a teenage girl board the far end of the train. The girl, only a couple years older than me, was carrying a baby and dragging a toddler along behind her. They were ragged and very poor -- their faces were streaked with dirt and their clothes were torn.

I watched as the girl and her children walked down the aisle of the train towards us, asking for money and food. And in every single row, no one helped them. Everyone just looked away. But I couldn't take my eyes off them. I felt so angry and ashamed -- both that no one did anything, and that there was nothing I could do to help.

That girl on the train -- and 600 million more girls like her -- is why the UN and member states must radically increase their investments in girls and place girls at the center of the new global development agenda. And that early experience is why I launched Let Girls Lead, an organization that has contributed to the health, education and livelihoods of more than 3 million girls globally since 2009.

Consider this: Research demonstrates that girls who complete seven years of schooling will marry four years later and have 2.2 fewer children than girls who do not complete primary school. Yet even though the economic and social returns of investing in girls are undeniable, World Bank research demonstrates that only two pennies of every dollar in international aid funding goes to support programs for girls.

In Davos last month at the World Economic Forum, UN Secretary General Ban Ki-Moon told world leaders that girls are the key to ending global poverty. Investing in girls is now proven to be one of the most cost effective strategies to improve health, education and economic outcomes for poor countries around the world.

Just like the girl on the train, there are 600 million girls living in poor countries who struggle to eat, attend school and see a doctor when they need one. These girls could be our own daughters -- bright, eager to learn, with dreams and hopes for the future. These girls could become doctors, entrepreneurs and leaders of their countries. These girls could change the world.

Reality, however, is very different. Most of these girls are forced to work while their brothers attend school, suffer abuse in their families and experience violence in their communities. They are too often married off as children to men three times their age, and give birth to daughters whose lives will follow the same cycles of exploitation.

Yet even in the face of poverty, violence and discrimination, these girls are not victims -- girls are powerful leaders and inspiring agents of change. Through Let Girls Lead, I have learned that when we invest in a girl, she will change her own life and her family's. And when we invest in girls' leadership and empowerment, the same girl will also change her community, her country and maybe even the world.

At the upcoming UN Commission on the Status of Women, Let Girls Lead will call on the UN and member states to double their investments in girls and prioritize girls' health and education in the post-2015 development agenda. During CSW, Let Girls Lead will share the UN Foundation's external evaluation of our work, demonstrating girls' power to transform their own lives, families, communities and the world. We will also host the global film premiere of PODER, a documentary about two Guatemalan girls who overcame enormous obstacles to improve their community, ensuring that girls can attend school and stay healthy.

Let Girls Lead's model is now the foundation for Champions for Change, which is building a movement of Champions advocating for improved reproductive, maternal, newborn and child health in Nigeria. Let Girls Lead and Champions for Change drive sustainable change through the passage of national laws and programs that save the lives of women, newborns and children, and ensure girls' access to quality healthcare, education and economic opportunity.

The world's 600 million girls are our greatest return on investment. The time has come for our dollars to follow our research and our rhetoric. As a global community, we can no longer afford to look away.