Casey and Shannon McLaughlin, pictured with their twins, Grace, left, and Grant, right, plan to file suit in federal court challenging the constitutionality of the Defense of Marriage Act. (Courtesy of Casey and Shannon McLaughlin)

The suit comes five weeks after the Pentagon ended its ban on gays in the military.

Lawyers plan to file suit in federal district court in Boston, the same court that ruled last year that the federal Defense of Marriage Act is unconstitutional because the law interferes with a state’s right to define marriage. The decision in on appeal to the U.S. Court of Appeals for the 1st Circuit.

The 1996 law bars federal recognition of same-sex marriages performed in states that allow them.

The suit also challenges provisions of federal code regarding spouses that lawyers said bar gay couples from accessing a range of benefits provided by the Pentagon and Department of Veterans Affairs, including military identification cards, access to bases, recreational programs, spousal support groups and burial rights at national cemeteries.

Massachusetts Army National Guard Maj. Shannon McLaughlin, 41, and her wife, Casey, 34, are serving as lead plaintiffs in the suit, which also includes five other troops and two career Army and Navy veterans.

The couple, from Foxboro, Mass., married in Dec. 2009 and have 10-month old twins. Though Shannon pays for the twins’ health care through her military benefits, Casey, a former high school history teacher who gave birth to the twins, must pay about $700 monthly for a separate health-care account, the couple said.

“What Shannon and Casey are seeking is the same treatment that their straight counterparts, who are legally married, receive every day without question and take for granted,” said Aubrey Sarvis, executive director of Servicemembers Legal Defense Network, a group that represented troops discharged for violating “dont' ask, don’t tell.”

Since the gay ban ended, Shannon said the couple no longer faces the anxiety associated with possibly losing her job for being gay.

But Casey said they now face “a different anxiety” that involves juggling different health-care accounts and preparing for Shannon’s possible overseas deployment. If Shannon deploys, Casey would be barred from taking the twins to regular medical appointments at a nearby military base, the couple said.

The ban means the military “is creating a second-class service member,” Shannon said. “It’s amazing to me how many other similarly-situated families there are out there.”

Sarvis said several potential plaintiffs backed out of the suit for fear of retribution from military commanders.

“It’s a big deal to sue any employer, but when in the military — when you hope to make a 20 or 30-year career — or you hope to make the next promotion, you think two or three times before doing this,” Sarvis said.

Dozens of legal challenges to DOMA are making their way through the federal court systems, but gay rights legal advocates have said they do not anticipate any decision on the issue by the Supreme Court until 2013.

The Obama administration decided earlier this year it would no longer defend the law, as several couples in states recognizing gay marriage began filing suit. In response, House Republicans tapped former solicitor general Paul D. Clement to defend the law. The office of House Speaker John A. Boehner (R-Ohio), who hired Clement, referred questions Wednesday to Clement’s office; he did not respond to reporter inquiries.

Pentagon spokeswoman Eileen Lainez said Wednesday that officials are “engaged in a careful and deliberate review” of whether some benefits could be extended to same-sex partners.

“Service members continue to have some benefits for which they may designate beneficiaries, regardless of sexual orientation,” Lainez said in an e-mail. But eligibility for other benefits is restricted by DOMA, she said.

At Veterans Affairs, spokesman Josh Taylor said department lawyers plan to review the case once it is filed.

Follow Ed O’Keefe on Twitter: @edatpost

Further reading:

‘Don’t ask, don’t tell’ ends, troops mark the day in different ways

Same-sex marriage cases wind their way to Supreme Court as political climate changes

In gay rights victory, Obama administration won’t defend Defense of Marriage Act

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