Former Irish President Mary Robinson was just making a polite conversation with an Ethiopian   teenager about her wedding day. The 16yearold had already been married for a year. "She looked at me with the saddest eyes and said, 'I had to drop out of school'," Robinson said in a telephone interview. "That conveyed to me the reality," said Robinson, the first woman to serve as Ireland's president and former U.N. high commissioner for human fights. "Her life, as far as she is concerned, had more or less ended." Robinson said keeping girls in school was one of the most important things policymakers could do to address the coming challenges of an ever-increasing population, predicted by the United Nations to reach 7 billion soon. "European countries are concerned about aging populations as is Japan, but this is much less of an issue than the huge number of people which we are going to see over the next 40 years when the population goes from 7 billion to 9 billion," she said. "Almost all of that increase will be in poor developing countries, so that we have a very big challenge." Family planning experts worry in particular about the future population explosion in subSaharan Africa. In May, the United Nations projected the world population would reach 9.3billion in 2050 and 10.1 billion by 2100. Much of that growth will come from Africa, where the population is growing at 2.3 percent a year--more than double Asia's 1 percent growth rate. If that rate stays consistent, which is not certain, Africa's population will reach 3.6 billion by 2100 from the present 1 billion. Joel Cohen, a professor of population studies at Rockefeller University and Columbia University in New York, said universal secondary education offered a way to reduce population in high birthrate regions. In addition to providing information about birth control, a secondary education teaches women to reduce their own fertility  , improve the health of their children and allows them to move from a mindset of having many children, in the hopes that some will survive to improving the quality of each child's life, Cohen wrote in the journal Nature. According to Robinson, what is one of the most important things policymakers can do to prevent the population from increasing rapidly?
Keeping girls in school. Letting girls go away from Africa. Letting young girls remain single. Keeping girls in families.