If you think concerns about population today are overblown, you should take a look at the 2013 Failed States Index (FSI) that was formally released by the Fund for Peace and Foreign Policy magazine at a Washington, D.C. press conference on Tuesday. The annual ranking of countries that are struggling against great odds to maintain functioning governments reads like a "Who’s Who" of countries with rapidly growing populations. Large parts of the world have made–in full or in part–the demographic transition from high fertility, high mortality, and rapid population growth rates to low fertility, low mortality, and stable or declining populations. Dozens of countries, however, have failed to make that transition, and, almost without exception, these countries rank very low in contraceptive usage and very high in terms of hunger, poverty, disease, and political instability.

The populations of the 20 countries that had the worst scores in the 2013 Failed States Index currently total 813 million. According to the latest UN population projections, their numbers will more than double in the next 37 years. Unless fertility rates in these countries fall faster than presently anticipated, their populations will total 1.7 billion by 2050. Today these 20 countries constitute 11 percent of world population today; by 2050 they could account for 18 percent. And without an increased and sustained commitment on the part of the U.S. and other donor nations to international family planning assistance, the UN’s latest population projection could turn out to be an underestimate.

Expanded access to contraceptives would help to lower fertility in these countries, but unless more girls stay in school and delay marriage to adulthood, the decline in fertility could easily stall. In some countries, it already has. In many countries, the adolescent pregnancy rate is rising. The mere fact that most countries in the world have undergone a demographic transition does not guarantee that all countries will.

In many of these struggling countries, forty percent or more of the population is under the age of 15, and these children will soon be entering their reproductive years. The population of Somalia, which topped this year’s FSI, is projected to rise from 10.5 million to 27.1 million by 2050. The population of Democratic Republic of Congress (DRC), which came in second on the index, is projected to rise from 67 million 155.2 over that same time period. Sudan, which came in third, is projected to jump from 38.0 million to 77.1 million. The population of Yemen, already suffering from acute water scarcity, is projected to rise from 24.4 million to 42.5 million. The populations of war-torn Iraq and Afghanistan are also on the rise. Iraq’s population could climb from 33.8 million to 45.9 million by mid-century, while Afghanistan’s population could jump from 30.6 million to 56.6 million. But none of these projections are written in stone. Even small declines in fertility rates could dramatically lower these long range population forecasts. But will they?

By any fair measure, providing contraceptive services is not expensive. What’s really costly is failing to provide women with contraceptives choices and denying them the freedom to choose how many children to have and when. Reproductive freedom, as it turns out, is crucial to the future of failing or potentially failing countries. Without it, many of these countries will never complete the demographic transition to lower fertility and lower mortality, and they will have great difficulty in reducing poverty, eliminating hunger, and maintaining political stability.

When women everywhere enjoy gender equality and access to family planning and reproductive health services, World Population Day will be a cause for universal celebration, but we are not there yet. The UN set 2015 as the target year for achieving universal access to family planning and reproductive health services, but far too little progress has been made. Over 200 million women in the developing world want to avoid or delay a pregnancy, but are not using a modern method of contraception. Empowering these women and giving them access to a range of contraceptive services is crucial to their health and the wellbeing of their families and their country.