Almost 100 years ago Margaret Sanger opened a tiny birth-control clinic in the Brownsville section of Brooklyn, N.Y. Poor Yiddish- and Italian-speaking women, overwhelmed by large families that they could not support, would come for advice about how to avoid pregnancy and the dangers of horrific, sometimes life-threatening, self-administered abortions. The clinic taught women to use the diaphragm. Nine days after it opened, Sanger and two other women who ran the center were jailed for violating a New York State law that prohibited contraception.

This clinic eventually grew into Planned Parenthood, the nation’s largest nonprofit supplier of reproductive health services to women and men. A century after its founding, the organization is again at the heart of one of the most divisive issues in American political life. It has come under attack by Republican presidential candidates seeking to revoke the group’s federal funding—almost half of its $1-billion budget comes from federal and state sources. Last year the House of Representatives voted to withdraw some of its support, although the measure was not sustained in the Senate. (Backing for the group, initiated under the Nixon administration, has not always been a partisan issue.) In March, Mitt Romney, the GOP’s presumptive presidential candidate, vowed to end federal funding if elected. This is a worrying prospect for both women and public health.

For some people, Planned Parenthood has come to symbolize abortion, which it has provided since 1970. But in all the rhetoric, facts have sometimes gone missing. For instance, Senator Jon Kyl of Arizona declared last year on the floor of the Senate that abortion accounts for “well over 90 percent” of what Planned Parenthood does. The actual figure is 3 percent. (Planned Parenthood clinics perform one in four abortions in the U.S. but use no federal funds for this practice.) To some abortion opponents, that 3 percent is reason enough to gut the organization. If a future Congress and White House were to do so, however, it would drive women once again into the back alleys, without necessarily decreasing the number of abortions.

Stripping Planned Parenthood of federal funding would also sacrifice the 97 percent of its public health work that has nothing to do with abortion, from which many people benefit directly. One in five American women have used the group’s services, and three out of four of its patients are considered to have low incomes. In 2011 it carried out tests and treatment for more than four million individuals with sexually transmitted diseases. It supplied 750,000 exams to prevent breast cancer, the most common cancer among U.S. women. And it performed 770,000 Pap tests to prevent cervical cancer, which was a leading cause of death among women before this screen became widely available. Planned Parenthood is one of the most important public health care institutions in the country, even aside from its work in rational family planning.

Family planning has benefited society in numerous ways. It has saved lives, opened new horizons for women and kept populations from soaring. Since 1965, the year the Supreme Court struck down a Connecticut law that made access to contraception illegal, women’s ability to plan and space out pregnancies has contributed to a 60 percent decline in maternal deaths. By 2002, moreover, only 9 percent of births were unwanted, compared with 20 percent in the early 1960s. As a major provider of contraceptives—it furnished birth control to two million Americans last year—Planned Parenthood serves as “America’s largest abortion preventer,” as one Chicago Tribune writer pointed out.

Access to birth control in the U.S. has helped narrow the income inequality gap between men and women by as much as 30 percent during the 1990s alone. The pill has given women greater choice about when to have children, freeing them up to acquire career skills. By 2009 women procured more than half of all U.S. doctoral degrees, compared with 10 percent in 1960. The health and well-being of a society correlates highly with the status of its women. In many parts of the Middle East, Asia and Africa, women are now making gains, to the betterment of all, in access to education and jobs—both contingent on family planning. Now is a particularly bad time for Americans, as citizens of the world, to forget what we have accomplished at home.

This article was published in print as "Protect Women's Health."