When former Indiana Senator Birch Bayh* wrote Title IX forty years ago, his goal was very simple: to make sure women could get a good education. He wanted to force schools to accept women as students, let them into classes, and hire them as professors. And he wanted to make professions that require higher education accessible to women.As the law, which prohibits educational programs that take federal money from discriminating on the basis of sex, celebrates its fortieth birthday on Saturday, the changes Bayh was after have, to a stunning degree, happened—women have been earning more undergraduate degrees than men since 1996 and in 2009 overtook them in the attainment of doctoral degrees; 47 percent of legal degrees and 48 percent of medical degrees were conferred on women in 2010, compared to 7 percent and 9 percent, respectively, in 1972. Title IX has become most famous for ushering female athletes onto the playing field—an application of Bayh’s law that he told me didn’t cross his mind when he was defending it in the Senate.Another of the most lasting—and most controversial—legacies of Title IX is, likewise, in an area referenced nowhere in its 37 words: sexual harassment. The law made national headlines once again last spring when the Department of Education’s Office of Civil Rights announced that it would investigate whether Yale was violating Title IX by allowing a hostile sexual environment. How did a law written to open the doors of classrooms become the staging ground for lawsuits over sexual misconduct?