May is Teen Pregnancy Awareness Month in the United States, where a recent Journal of Pediatrics report shows a drop in teen pregnancy by almost half since 1991. This demonstrates significant progress in public health efforts to diminish the number of “children having children” in America. Unfortunately, the statistics tell a different story in many other parts of the world.

While births to girls ages 15 to 19 have fallen to 31.3 per 1,000 in the United States, the percentage of teenage girls giving birth in some other parts of the world is still alarmingly high. In Niger, for example, more than half of adolescent girls (15-19) give birth before they turn 18. Why the disparity?

The drop in teen pregnancies in the United States is almost certainly due to a wider prevalence of safe sex, made possible by increased access to contraceptives. As Medical Daily recently reported, “Although teenage pregnancies are down significantly, the rates of teens having sex isn't. This indicates that teens are choosing to practice safe sex when they do choose to have sex.”

Millions of teenage girls across the world are, or will be, practicing unsafe sex, and far too many lack access to information, contraceptives and basic education in the fundamentals of sexual and reproductive health. Data gathered by UNFPA, the United Nations Population Fund, suggest that an unmet need for family planning exists among 33 percent of girls between 15 and 19 years old who are currently married (or in union) in Ethiopia, 38 percent in Bolivia, 42 percent in Nepal, 52 percent in Haiti and 62 percent in Ghana. This means that not even half of the demand for family planning among married or in-union girls in all these countries is being satisfied.

More adolescent girls in the developing world are married as compared to their counterparts in developed nations, a fact that drives the high adolescent birth rate. And research has shown that adolescent girls who marry young and become mothers at a young age are likely to be disadvantaged throughout their lives. “The evidence is clear,” say UNFPA analysts in Adolescent Pregnancy: A Review of the Evidence. “For girls, marriage and motherhood too soon of the too young, bring negative impacts on girls' rights to education and health, to life opportunities and indeed, to life itself.”

Contributing to the persistently high birthrate in many areas of the world are social, religious and cultural norms that encourage child marriage. As the Adolescent Pregnancy analysis concludes, “these traditional practices are harmful because they violate the rights of girls, with life-threatening consequences to their sexual and reproductive health and reproductive rights.” In UNFPA’s view, no cultural argument should take precedence over the rights and well-being of adolescent girls.

Overall, what we are seeing is a teen pregnancy divide, with birthrates declining among the more affluent, more educated and more urban global populations. This, in turn, perpetuates a vicious cycle in large parts of the developing world, as too many adolescent girls there – married and unmarried – become pregnant at too young an age, abandon their education and do not contribute their full potential to their local and national economies.

Breaking this cycle and closing the teen pregnancy divide will require a commitment from nations, communities and individuals in both developed and developing countries. For starters, governments should enact and enforce national laws that raise the age of marriage to 18 for both girls and boys and promote community-based efforts to prevent child marriage and its consequences. Girls that get married too young often become mothers too soon. This hinders their ability to fully contribute to the development prospects of their families, communities and nations.

Second, nations in the developing world should further embrace the need for access to reproductive health commodities and prioritize family planning services in their healthcare budgets. Where money is an issue, multilateral institutions will have to support these governments to meet this need. At the local level, communities should provide the infrastructure to deliver these commodities and services in an environment that respects the privacy of the recipients.

Underlying all of these efforts is the notion that the dignity and human rights of adolescent girls must be protected, including the right to decide when and whom to marry. Every young girl, no matter the accident of chance that determined where she was born, or her economic circumstances, has the right to fulfill her human potential. It’s about making informed choices. Today, too many are denied that right. We can change that, and we must.

Osotimehin is a United Nations under-secretary-general and executive director of the United Nations Population Fund.