Google, Starbucks and Microsoft are among the 70 companies that have filed an amicus brief opposing the Defense Of Marriage Act (DOMA), the 1996 law that bars federal agencies and the military from recognizing the legal marriages of gay and lesbian couples.

In their filing in support of a legal challenge to the law, the companies argued that the law forces them to treat their employees differently.

“Because marriages are celebrated and recognized under state law, a federal law withholding marital benefits from some lawful marriages, but not others, creates a non-uniform rule. Employers are obliged to treat one employee spouse differently from another, when each is married, and each marriage is equally lawful,” the companies said in their brief.

Joe Solmonese, president of the Human Rights Campaign (HRC), the nation's largest gay rights advocate, said the filing shows that DOMA hurts business.

“Not only does DOMA hurt families, now we have a clear picture of how it also harms American business,” Solmonese said in a statement. “With a majority of Americans also opposing this law, the time has come for the federal government to treat all legally married couples equally.”

Other companies signing on to the brief include CBS, Levis Strauss, Nike and Time Warner Cable.