BOSTON (AP) – As if tax season isn’t stressful enough, same-sex newlyweds in Massachusetts are pondering what should be a simple question: Do they check “married” or “single” on tax forms for the federal government that doesn’t recognize their union?

A landmark court ruling made Massachusetts the first state to sanction same-sex weddings nearly a year ago, but same-sex couples will have to untie the knot, on paper, by declaring themselves “single” to the IRS.

Or not, in some cases.

“I fully intend to file married joint return, regardless of the fact the we’re not supposed to,” said Arthur Henneberger, 46, of Springfield. “If they kick it back, fine, we’ll go to court.”

Ultimately, GLBT advocates who pushed to get same-sex marriage legalized in Massachusetts hope to overturn the federal Defense of Marriage Act, which defines marriage as a union between a man and a woman.

But for now, the Gay & Lesbian Advocates and Defenders aren’t looking to pick a fight with the IRS.

“It’s not something that should be done quickly or precipitously,” GLAD spokesperson Carisa Cunningham said. “We wouldn’t advise anyone to try to do it alone.”

Instead, the group is advising the state’s estimated 4,900 same-sex couples who married in the past year to file federal returns as if they are single, but to note either through an attached letter or on the return itself that they were married in Massachusetts.

Seven same-sex couples who had been denied marriage licenses across the state sued, leading to the landmark ruling by the state Supreme Judicial Court that legalized same-sex marriage.

A wave of same-sex weddings took place when the ruling took effect May 17, and sparked a social revolution when the mayors of San Francisco and New Paltz, N.Y., issued thousands of marriage licenses to same-sex couples, which were later declared invalid.

On Election Day, however, ballot questions prohibiting same-sex marriage in 11 states prevailed. Even in Massachusetts, the Legislature last year gave preliminary approval to a proposed constitutional amendment that would ban same-sex marriages but simultaneously legalize civil unions.

Julie and Hilary Goodridge, the lead plaintiffs in the lawsuit, plan to follow GLAD’s advice and file separate single returns to the IRS, along with a letter noting their marriage.

“I don’t want to do something that’s not legal, frankly, whether it’s discriminatory or not,” Julie Goodridge said. “I consider it every single day, but I won’t do it.

“We created a lot of change in this state,” she said. “There’s a lot of ways that we’re incredibly lucky. We were able to get married in our home state. If I have to wait two or three or four more years to file a joint federal tax return, then I’m willing to wait.”

IRS spokesperson William Cressman said the agency has issued no guidance regarding same-sex couples.

“We’re going to follow the Defense of Marriage Act,” he said. “We’ve not given any other guidance.”

If the IRS catches same-sex couples filing as “married” on their federal tax returns “the status would be changed and they would be notified of that,” Cressman said.

The IRS would bill the filer for any overdue amount, plus interest, and possibly levy a fine. Cressman said, however, that if people pay up with interest, they likely wouldn’t get fined.

Cases vary widely, but there’s little financial difference between filing as single or as married, Cressman said.

The IRS won’t discuss its audit criteria, but Cressman added: “We are always looking to make sure that tax returns are accurate and filed correctly.”

Opponents of same-sex marriage say same-sex couples who file federally as married are out of line.

“We need to respect the laws of the land,” said Kris Mineau, president of the Massachusetts Family Institute. A same-sex marriage joint return “would be a fraudulent return and they would be subject to prosecution.”

Filers are permitted to write comments on their returns, but those comments are ignored when it comes time to calculate tax payments or refunds, Cressman said. He noted that electronic filers don’t have that option.

“It’s hard enough to be different,” Bob Murch said. “I don’t understand why the government needs to see me as gay. I pay my taxes, I go to work, I’m a good person.”

Murch and husband Gary Halteman’s tax preparer advised them to file “single” federal returns along with a certified letter and copy of their marriage certificate. But the couple, who live in Salem, haven’t decided what they’ll do.

“If you say you’re single, you’ve actually lied on your taxes,” said Murch, 30.

Murch, who, like his husband, works for a financial investment firm in Boston, says he won’t be offended if he has to file as single.

“In any civil rights struggle there’s always bumps in the road,” he said. “It’s just part of what we need to change.”

Henneberger, of Springfield, who married his partner of 23 years, Donald Smith, who changed his last name to Henneberger, said he won’t consider filing as single.

“We’re not second-class citizens. The fact is, we’re married,” he said.