A federal appeals court ruled unanimously Thursday that the Defense of Marriage Act unconstitutionally denies federal benefits to married gay couples, the Associated Press reported.

The act is a federal law enacted in 1996 that defines marriage as the legal union of one man and one woman. The three-judge panel of the 1st U.S. Circuit Court of Appeals in Boston said the act could not be justified under current precedents that protect minorities and other groups from discrimination, according to the Washington Post.

Also under the law, no state that does not allow same-sex marriage is required to acknowledge a same-sex marriage that is legal in another state. The courts did not rule on this provision, the Associated Press reported.

The panel said only the Supreme Court will be able to determine whether the federal government must recognize same-sex marriage from states where they are legal, according to the Washington Post.

The Associated Press article called this a “groundbreaking ruling all but certain to end up before the Supreme Court.”