Opening the door to a potentially historic step in the nation’s gay rights movement, the U.S. Supreme Court on Dec. 7 agreed to decide two constitutional challenges involving same-sex marriage.

The justices will hear arguments in Hollingsworth v. Perry, which asks whether the U.S. Constitution’s 14th Amendment bars California from defining marriage as between a man and a woman. The second challenge is U.S. v. Windsor, raising the question of whether Section 3 of the federal Defense of Marriage Act (DOMA) violates the equal-protection guarantee of the Fifth Amend­ment as applied to same-sex couples who are legally married under their state laws.