Like many of Jamaica Plain’s married couples, Bette Jo Green and Jo Ann Whitehead enjoy a backyard garden, join in neighborhood barbecues and mark milestone anniversaries together. But unlike most couples, they have been forced to battle the federal government for basic marriage benefits such as Social Security—a case that looks likely to head to the U.S. Supreme Court.

Green and Whitehead are among the plaintiffs in a landmark lawsuit challenging the federal Defense of Marriage Act (DOMA), which denies many benefits to same-sex spouses. The First Circuit Court of Appeals in Boston ruled last month that DOMA’s denial of benefits in the case is unconstitutional.

“I feel that people want us to be part of the community,” Whitehead said in a Gazette interview with the couple, about the local friendliness toward same-sex couples. “DOMA is one of the ways we don’t feel like part of the community.”

Now in their late 60s, the couple is retired—Green is a former nurse, Whitehead the creator of Boston Natural Area Network’s Master Urban Gardener program—and both of them have successfully battled cancer. After full careers and 30 years together, they are already denied Social Security and tax benefits that opposite-sex married couples receive. Now they worry about the further loss of benefits if one of them outlives the other.

The unequal treatment is a far cry from the embracing Green and Whitehead received when they moved to McBride Street in 1981.

“There was just an amazing diversity we stumbled into,” said Green, recalling neighbors who were “German, Irish, straight, gay, African-American, Chinese. We thought, ‘This is neat. It’s very comfortable.’”

Whitehead recalled the young couple being “adopted” by one local family.

The couple married in their back yard in 2004 after another landmark lawsuit with several JP plaintiffs legalized same-sex marriage in Massachusetts. At first, DOMA was far from their minds, as it had been for years.

DOMA was enacted in 1996 when it appeared that Hawaii might legalize same-sex marriage.

“I don’t think I even fully understood all the potential negative ramifications of DOMA [in 1996],” Whitehead said. “I saw it as a slam against gays and lesbians.”

“I didn’t really assume we were going to be married at all,” Green recalled, saying that she and Whitehead were already a committed couple in 1996.

After their marriage in 2004, the couple was contacted by Gay & Lesbian Advocates & Defenders (GLAD), a Boston-based civil rights organization that carefully selects plaintiffs for major lawsuits against possibly discriminatory laws. GLAD had spearheaded the lawsuit that led to the legalization of same-sex marriage in the state, and next was looking to challenge DOMA.

GLAD sent Green and Whitehead a questionnaire asking about any troubles they had in receiving benefits. At the time, Green was working at Brigham and Women’s Hospital, which provided domestic-partner benefits. But as her retirement approached and another GLAD questionnaire arrived, the couple rethought the situation.

“I realized that we would have some problems in terms of Social Security benefits and that type of thing,” Green said.

GLAD interviewed the couple and added them as plaintiffs to the suit known as Gill v. Office of Personnel Management.

“I think it had to do with our gray hair,” Green joked.

GLAD does the legal work, while the plaintiffs are the case’s public face.

“They’ve asked us to be the people who tell the real, everyday story,” Green said, “so people can say, ‘Oh, that’s not fair. That needs to be fixed.’”

Whitehead said the plaintiffs have bonded from the experience. “We’re in awe of them,” she said, explaining that most of the others have more difficult personal situations than she and Green do.

Most legal observers believe that Gill (along with a companion suit filed by the state of Massachusetts) is headed to the Supreme Court on appeal and will make history as the high court’s first ruling about same-sex marriage.

Green and Whitehead, along with the other plaintiffs, are scheduled to attend any Supreme Court hearings in Washington, D.C. But they have differing expectations about the likely outcome.

Whitehead said she feels positive that the high court would rule DOMA unconstitutional, and that there is “the possibility of opening more doors than closing them.”

Green said she is not sure that the Supreme Court will strike down DOMA in this case, but she thinks it eventually will.

“I feel as if, as so many people have said, we’re on the right side of history,” she said.