Few issues have generated more controversy in America than whether biological males should be allowed to compete on girls’ and women’s school sports teams. Now, in a 6-3 decision, the Supreme Court has ruled that states may protect biological females from having to compete against biological males without violating the Constitution’s Equal Protection Clause or Title IX.

It’s important to understand what the Court did—and didn’t—decide. The ruling doesn’t require states to adopt those protections. It simply says they are free to do so.

That matters because the decision explicitly affirms a basic truth: men and women are physically different. Recognizing that reality is not discrimination. It is a legitimate basis for protecting fairness in girls’ and women’s sports. And it leaves those policy decisions where they belong—with the people and their elected representatives.