The US Supreme Court has declined to hear a case brought by the National Coalition for Men which sought to have the federal requirement that all men age 18-26 be registered with the Selective Service be expended to include women. The Court did not comment on any reasoning in an official opinion however Justice Sonia Sotomayor wrote that she agrees with the decision because the Court has a long-standing precedent to defer to Congress on matters of national defense and the military, and especially since Congress is considering making the military draft registration a requirement for both men and women. Justices Stephen Breyer and Brett Kavanaugh also signed Sotomayor’s opinion.
Under the Military Selective Service Act, all men turning 18 are required under federal law to register with the Selective Service and keep their address updated with the agency until they turn 26. It is the last federal law that specifically singles out one sex for a requirement under a law or regulation.
The Supreme Court last ruled on a case challenging the men-only registration in 1981 in the Rostker v. Goldberg case and ruled that it can remain a male only requirement and reasoned that since women were not allowed to service in combat roles at the time there was no need to draft women, thus there was no need to women to be included in the Selective Service requirement. In 2013 the Department of Defense lifted its ban on women serving in combat and in 2015 all roles in the military were open to both men and women.