This is a 5:37 p.m. update of a story originally posted at 12:26 p.m.

By DENISE LAVOIE

Associated Press

BOSTON - Massachusetts, the first state to legalize gay marriage, sued the U.S. government Wednesday over a federal law that defines marriage as a union between a man and a woman.



The federal Defense of Marriage Act interferes with the right of Massachusetts to define and regulate marriage as it sees fit, Massachusetts Attorney General Martha Coakley said. The 1996 law denies federal recognition of gay marriage and gives states the right to refuse to recognize same-sex marriages performed in other states.



The lawsuit, filed in federal court in Boston, argues the act "constitutes an overreaching and discriminatory federal law."



The lawsuit challenges the section of the law that creates a federal definition of marriage as limited to a union between one man and one woman.



Before the law was passed, Coakley said, the federal government recognized that defining marital status was the "exclusive prerogative of the states." Now, because of the U.S. law's definition of marriage, same-sex couples are denied access to benefits given to heterosexual married couples, including federal income tax credits, employment benefits, retirement benefits, health insurance coverage and Social Security payments.



"In enacting DOMA, Congress overstepped its authority, undermined states' efforts to recognize marriages between same-sex couples, and codified an animus towards gay and lesbian people," the lawsuit states.



The Defense of Marriage Act was enacted when it appeared Hawaii would soon legalize same-sex marriages and opponents worried that other states would be forced to recognize them. It defines marriage as "a legal union between one man and one woman as husband and wife" and defines "spouse" as "a person of the opposite sex who is a husband or a wife."



President Obama has pledged to work to repeal the law, although gay rights activists criticized the administration last month after Justice Department lawyers defended it in a court brief. White House aides said they were doing their jobs to support a law that is on the books.



Besides Massachusetts, five other states - Connecticut, Vermont, New Hampshire, Maine and Iowa - have legalized gay marriage.



This is the second lawsuit filed in Massachusetts challenging the law.



In March, the Boston-based Gay & Lesbian Advocates & Defenders claimed the law discriminates against gay couples and is unconstitutional because it denies them access to federal benefits that other married couples receive, such as health insurance and pensions.



Arline Isaacson, co-chairwoman of the caucus, said the lawsuit is bold and important.



She said Coakley is the first attorney general in the nation to challenge the defense of marriage law.



"It shows a lot of leadership and creative legal thinking on behalf of the state," Isaacson said. "Not only is she using a leadership position to support equality for the gay community, she is also protecting the state's right to treat its citizens equally."

But Kristian M. Mineau, president of the Massachusetts Family Institute in Woburn, criticized Coakley's move. He said the federal marriage act has been upheld in the past by federal courts.



Mineau said Coakley is looking at higher office.



"We believe it's a frivolous suit," Mineau said. "It's obviously a political move by the attorney general."

Dan Ring, staff writer for The Republican, contributed to this report.