The U.S. Supreme Court agreed Tuesday to review a piece of U.S. citizenship law that treats men and women differently.

The justices said they will hear a case about a law that applies only to children born outside the U.S. to one parent who is an American and one who is not. The law makes it easier for children whose mother is a citizen to become citizens themselves. Even after reform legislation in 1986, children of American fathers face higher hurdles claiming citizenship for themselves.