A lawyer for gay married couples argued Wednesday that a law that denies them a host of federal benefits given to heterosexual couples amounts to "across-the-board disrespect" and should be struck down as unconstitutional.

The 1996 federal Defense of Marriage Act, which defines marriage as a union between a man and a woman, is being challenged in two cases before the 1st U.S. Circuit Court of Appeals. The law also prevents the federal government from recognizing same-sex marriages.

In arguments to the court, Paul Clement, a lawyer for the Bipartisan Legal Advisory Group, defended the law, saying Congress had a rational basis for passing the law known as DOMA in 1996, when it appeared Hawaii would become the first state in the nation to legalize gay marriage and opponents worried that other states would be forced to recognize such marriages.

Clement said Congress wanted to preserve a traditional and uniform definition of marriage. He also argued that Congress has the power to define the terms used in federal statutes to distribute federal benefits.