Why would a state prevent boys and girls from dancing together? It’s one of those cases of perverse incentives in law. Title IX is a federal statute requiring schools to offer both sexes equal access to educational opportunities. In order to demonstrate compliance, states want to get as many girls in sports as boys, but some popular sports like football are male-dominated and have no female equivalent. So, in the case of South Dakota, the state decided that dance would be exclusively a girls sport — boys would not be allowed to dance. The libertarian Pacific Legal Foundation fought that rule on behalf of Freddie Linden, a talented boy who was shut out of his school’s dance team. They won.