The ruling came from U.S. District Judge Jeffrey White in San Francisco who was appointed by Republican President George W. Bush.

Congress passed DOMA in 1996 and President Bill Clinton signed it into law. It prevents same-sex couples who are legally married in a handful of states from enjoying more than 1,000 federal benefits awarded to heterosexual married couples.

Rita Lin, an attorney for the plaintiff, said on Wednesday that White's ruling could have wide implications for same-sex couples in areas like tax and pension benefits.

"The reasoning of the opinion applies to anyone who has been discriminated against under DOMA," Lin said.

Attorneys for the House of Representatives could not immediately be reached for comment.

Plaintiff Karen Golinski has worked as a staff attorney for the 9th U.S. Circuit Court of Appeals in San Francisco for over 20 years.

She sued the U.S. government after it refused to enroll her spouse, Amy Cunninghis, on her federal family health insurance plan. The couple married during a five-month legal window in California before voters in 2008 passed Proposition 8, a gay marriage ban.

The case is one of a handful around the country challenging DOMA. A Massachusetts federal judge also struck down DOMA in 2010, and that ruling is currently on appeal.

Attorneys for the U.S. Department of Justice initially argued that DOMA prohibited Cunninghis from receiving the same benefits as she would receive if Golinski were a man.

Last year, however, Attorney General Eric Holder and President Barack Obama called DOMA unconstitutional and said that while they would continue to enforce it, they would quit defending it in court.

In response, the U.S. House of Representatives - which is controlled by Republicans - stepped in to defend the law.

In his ruling on Wednesday, White wrote that animus towards gays "is clearly present" in the legislative history from when the law was passed. The federal government has traditionally refrained from inserting itself into spousal relations, White wrote.

"The Court finds that the passage of DOMA, rather than maintaining the status quo in the arena of domestic relations, stands in stark contrast to it," White wrote.

White issued a permanent injunction preventing the government from further interfering with Golinski's ability to enroll her wife in the insurance program.

The House of Representatives could appeal White's ruling to the 9th U.S. Circuit Court of Appeals, which recently found California's gay marriage ban unconstitutional. Supporters of Prop 8 have asked the court to revisit its ruling.

The DOMA case in U.S. District Court, Northern District of California is Karen Golinski vs. United States Office of Personnel Management and John Berry, 10-257.

(Reporting By Dan Levine; Editing by Eric Beech and Cynthia Osterman)

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