Induced abortion is a common medical procedure in the United States and the world. The Alan Guttmacher Institute, a private organization that researches reproductive health issues, estimates that about 46 million women—35 out of every thousand women of childbearing age—have an abortion each year. In the United States, where abortion rates have been declining since 1990, approximately 1.4 million women have an abortion each year. According to the institute, 43 percent of American women will have an abortion at some point in their lifetimes.

Although it has become commonplace, abortion has been a polarizing social policy issue in the United States since at least 1973, when the Supreme Court in the case of Roe v. Wade overturned state laws prohibiting or restricting the procedure. On one side of the debate are those who call themselves pro-choice and who believe that women have a fundamental right to...