Like any other military wife, McLaughlin, 35, worries about her spouse’s possible deployments, combat duty, and the mandatory weeks of training each year. But when the Massachusetts National Guard holds retreats for married couples to help them better cope with the stresses of military life, Casey McLaughlin is not invited.

That’s because she is married to a woman, Major Shannon McLaughlin, 42, who has been in the military for 14 years. Shannon was deployed to the Middle East just after 9/11. She was a third-year law student at Boston College when her Navy Reserve unit was activated for nearly a year. When she returned, she completed law school. In 2005, she switched to the Army National Guard, where she is a judge advocate general, or lawyer.

Casey Brennan and Shannon McLaughlin married in 2010, but did not tell anyone in the military for fear that Shannon would lose her job. “It was dangerous for me to reach out to other wives,” says Casey.

In early 2011, Shannon’s unit was preparing to deploy to Afghanistan while “Don’t Ask, Don’t Tell” was still in effect. Casey was six months pregnant, and Shannon decided she had to do something. “I took the very dangerous but necessary act of bringing her to a Yellow Ribbon event, which gets families ready for deployment,” says Shannon. “I knew I was going to be leaving my wife for a year with two new babies.”

No one said anything negative to them while they were there; under the rules, military personnel can bring anyone to the event, including a friend. “Shannon was not allowed, however, to introduce me as her spouse, otherwise she would have risked discharge,” says Casey.

In the end, Shannon’s unit was not deployed, and when “Don’t Ask, Don’t Tell” was repealed in late 2011, they felt somewhat safer as a couple.

In the shadows for so long, Casey and Shannon McLaughlin now feel the need to speak out on behalf of other military couples like themselves, who they believe have been treated like second-class citizens.

The time appears ripe: a US Supreme Court case on gay marriage is expected to be heard March 27; on Feb. 11, departing Defense Secretary Leon Panetta announced that 20 benefits will be extended to same-sex couples in the military, ranging from hospital visitation privileges to membership in family readiness groups; President Obama addressed the rights of gay and lesbian couples in his State of the Union speech; and a recent full-page ad in the New York Times quoted bipartisan leaders on the freeedom to marry.

In a major policy shift, the Obama administration in late Februrary filed a brief in the Supreme Court case declaring the Defense of Marriage Act, known as DOMA, “violates the fundamental constitutional guarantee of equal protection” by denying thousands of married same-sex couples “an array of important federal benefits that are available to legally married opposite-sex couples.”

Dozens of top Republicans have also signed a brief in support of gay marriage, including former advisers to President George W. Bush and former Massachusetts governors William Weld and Jane Swift.

After the November elections, a Gallup poll found that 53 percent of the public said that same-sex marriage should be legal. The McLaughlins are pleased at the Pentagon announcement that the military will now allow gay and lesbian personnel to receive some spousal benefits, but they feel it was late in coming and limited in scope.

“Before that announcement, Casey was absolutely invisible to the military,” says Shannon. “She was just like a roommate. She had no access to the base, no dependent ID card to get into the commissary, the base exchange, the bowling alley, swimming pool and lessons for the kids, the recreational activities, the discount tickets that make family life a little more enjoyable, a little easier.” The expanded benefits will not go into effect until Aug. 31 at the earliest, according to the Pentagon.

Shannon shops at the commissary, or military grocery store, at Hanscom Air Force Base in Bedford because of the discounted prices, but Casey is not allowed in by herself because she has no military spouse ID card.