Gay rights groups are cheering a federal appeals court ruling declaring the Defense of Marriage Act (DOMA) unconstitutional.

A three-judge panel of the First U.S. Court of Appeals in Boston on Thursday became the first appeals court to strike down the law when it unanimously upheld a lower court's ruling which found that portion of the law violates the constitutional rights of married gay and lesbian couples.

“Today's unanimous decision by the First Circuit Court of Appeals is a powerful affirmation that the so-called Defense of Marriage Act is an unconstitutional and unjust law whose days are numbered,” Evan Wolfson, founder and president of Freedom to Marry, said in a statement. “This ruling will return the federal government to its historic role of respecting marriages performed in the states, without carving out a 'gay exception' that denies thousands of protections.”

Currently 6 states plus the District of Columbia offer equal marriage rights. Lawmakers in Maryland and Washington have approved similar legislation but opponents have vowed to repeal the laws at the ballot box before each takes effect.

Under DOMA, the federal government does not recognize such marriages, blocking access to more than 1,100 rights, benefits and responsibilities, including Social Security survivor benefits, federal employee health benefits for spouses and the ability to file joint tax returns.

Aubrey Sarvis, executive director of Servicemembers Legal Defense Network (SLDN), which has filed its own DOMA legal challenge as it relates to gay troops, applauded the court's decision.

“At SLDN, we applaud the court for affirming that legal marriages in the states – and all the rights and protections that come with those marriages – should be recognized and respected by our federal government,” Sarvis said.