( CNN ) -- A legal advocacy group sued the federal government Tuesday , seeking benefits for 15 gay and lesbian Massachusetts residents who wed after the state legalized same-sex marriage . A lawsuit contends the federal government is denying benefits to Massachusetts same-sex couples . Gay & Lesbian Advocates & Defenders -- the same Boston-based group that successfully argued in 2003 for same-sex marriage rights in Massachusetts -- filed the lawsuit Tuesday in U.S. District Court in Boston on behalf of six couples and three men whose husbands have died . The suit contends the federal Defense of Marriage Act denies them protections and benefits that heterosexual couples receive , including health insurance for federal employees , the ability to file as `` married filing jointly '' on federal income taxes and Social Security spousal protections . Two other couples plan to file suit after they receive an anticipated rejection of their amended tax returns from the Internal Revenue Service , GLAD said . President Clinton signed the Defense of Marriage Act into law in 1996 . It effectively bars the federal government from recognizing same-sex unions by defining marriage as `` a legal union between one man and one woman as husband and wife '' and a spouse as `` a person of the opposite sex who is a husband or a wife . '' GLAD 's suit addresses only Section 3 of the law , a portion that prevents the federal government from giving Social Security and other protections to same-sex married couples . GLAD says there are 1,138 federal laws in which marital status is a factor . Only Massachusetts and Connecticut allow same-sex marriage . Vermont , New Jersey and New Hampshire allow civil unions . One of the plaintiffs in the suit is Dean Hara , who was married to former U.S. Rep. Gerry E. Studds , the first openly gay member of Congress . The two legally married in 2004 , a week after Massachusetts began issuing marriage licenses to same-sex couples . Studds , who by then had retired from politics , died in October 2006 . `` Gerry was a public servant for 27 years , worked hard for our country and paid as much into the system as anyone else , '' Hara , 51 , said , according to the GLAD Web site . `` But after he died , I was treated differently than other surviving spouses . Every federal employee counts on their surviving spouses having basic protections , but the federal government denies me those protections because of DOMA . '' Other plaintiffs include state trooper Sgt . Mary Ritchie and her spouse , Kathy Bush . They said not being able to file federal taxes jointly denies them deductions afforded to heterosexual married couples . `` We work hard , pay taxes , volunteer and do our part for our community . But the federal government still tells us we 're less of a family than other families in our neighborhood -- families Mary works to protect , '' Bush said , according to the GLAD Web site . Others named in the suit include a postal worker who has n't been allowed to add her spouse to her health plan , a widower who has n't been able to collect his spouse 's Social Security payments and a Social Security Administration retiree who is denied health insurance for his spouse . The United States of America and several federal agencies are named as defendants .
NEW : Suit addresses section of law that prevents Social Security benefits . US : Plaintiffs include surviving spouse of former U.S. congressman . Group says federal government denies same - sex marriage benefits , protections . Defense of Marriage Act bars federal recognition of same - sex marriage .