The Massachusetts attorney general asked a judge Wednesday to strike down a federal gay marriage ban, arguing it interferes with the right of states to define marriage and have those marriages acknowledged by the federal government.

The challenge to the constitutionality of the Defense of Marriage Act by Attorney General Martha Coakley's office was heard in federal court in Boston.

Assistant Attorney General Maura Healey argued states have historically had the right to define marriage.

She said the 1996 law could result in the denial of Medicaid and other benefits to married couples in Massachusetts, where same-sex unions have been legal since 2004.

A lawyer from the U.S. Justice Department, Christopher Hall, argued the federal government has the right to set eligibility requirements for federal benefits — including requiring that those benefits only go to couples in marriages between a man and a woman.

Hall also pointed to instances where the federal government has regulated the definition of marriage in certain immigration cases.