The world's population more than doubled in the last half-century and still is increasing. Absent an unexpected dramatic shift in family size or catastrophic increases in death rates, it could add 2.5 billion people before peaking. Worldwide, the largest group of young people ever is entering their reproductive years, requiring an expansion of family planning services to enable more couples to have the smaller families and later pregnancies they desire. In the long term, this will contribute to individual and family well-being, a slowdown in population growth and sustainable economic development.

Since 1965, Congress has appropriated money in the foreign assistance bill for population assistance to developing countries to advance the U.S. foreign policy goals of promoting sustainable development and health in these countries. This money supports family planning and related reproductive health services through programs administered by the U.S. Agency for International Development (USAID). Such programs directly benefit tens of millions of couples each year, improving both maternal and child health and contributing to slower population growth.

The President's Emergency Plan for AIDS Relief is a five year, US$15 billion initiative to fight the HIV/AIDS pandemic. Unfortunately, this assistance comes with significant restrictions on how the money is spent, undermining the public health impact of the funds.

In 2007, more than 6,800 people became infected with HIV every day, and new HIV infections outnumbered persons receiving treatment by nearly 3 to 1. Comprehensive HIV prevention-including both condoms and contraceptives-must become a top priority in the continued fight against HIV and AIDS. Because most HIV epidemics are fueled by sexual transmission of the virus, behavior change-including condom use-is critical to stemming the number of new infections.

The international community has repeatedly agreed to meet young people's developmental needs, including those relating to sexual and reproductive health. Yet young people often have little or no access to the information and services they need to make healthy, informed decisions about their sexual and reproductive lives.

Population age structure-the comparative size of specific age groups relative to the population as a whole-can help illustrate where countries' risks and opportunities lie in relation to critical issues such as democracy, development and security. In fact, the influence of age structure on a state's governance, risk of an outbreak of civil conflict, and economic development is both significant and quantifiable. Given these linkages, investments in family planning, infant and maternal health, education and economic opportunities for girls, women and young people can vastly affect the shape of things to come.

In 1994, at the International Conference on Population and Development (ICPD), 179 nations agreed on a plan for achieving universal access to basic reproductive health care by 2015. Today, vast differences remain in reproductive health status between rich and poor countries. The HIV/AIDS pandemic exacts a growing toll in human lives and threatens economic growth in some of the world's poorest countries. Donors focused on achieving the Millennium Development Goals – and concerned with poverty reduction, human rights, health and development – must help ensure the adequate flow of financial resources (referred to as population assistance) for sexual and reproductive health services.

The world's forests provide goods and services essential to human and planetary well-being. But forests are disappearing faster today than ever before. Due both to deforestation and human population growth, the current ratio of forests to human beings is less thn half what it was in 1960. Yet we not only need more forests, we need forests more than ever before–to protect the world's remaining plant and animal life, to prevent flooding, to slow human-induced climate change, and to provide the paper on which education and communication still depend. More efficient consumption of forest products and eventual stabilization of human population–a prospect that appears more promising today as birthrates decline–will be needed to conserve the world's forests in the coming millennium.

The United Nations Population Fund (UNFPA) provides international leadership on population issues and is a key source of financial assistance for family planning and reproductive health programs in poor countries. Restoring U.S. funding for UNFPA programs is crucial to improving the health and lives of women and their families and to addressing demographic trends and promoting sustainable development.