Men and women are equal, but we are not the same. Biological differences between the sexes are more than skin-deep, and profoundly shape our lives. The law must recognize this reality in certain circumstances, such as in sex-segregated sports teams or prisons, or it risks placing women and girls in harmful or even dangerous situations. An understanding of these differences will go a long way towards being able to tackle problems like sexual predation, instead of “solutions” that often gut basic fairness guarantees like due process or presumption of innocence.