Cesar Zapata and Hunter Carter: Because they were not a heterosexual married couple, American Airlines agents refused to screen Zapata and Carter together before issuing their boarding passes, Carter said. One rudely ordered Zapata back in line.

Cesar Zapata and Hunter Carter: Because they were not a heterosexual married couple, American Airlines agents refused to screen Zapata and Carter together before issuing their boarding passes, Carter said. One rudely ordered Zapata back in line.

(CNN) -- On his way home from a trip to Colombia, marriage equality advocate Hunter Carter discovered another way to fight for his rights.

Carter and husband Cesar Zapata stepped up to the American Airlines ticket counter in Medellin, Colombia, expecting to undergo a preflight security screening together, just like heterosexual married couples.

That didn't happen, even though the United States Supreme Court struck down part of the Defense of Marriage Act in late June, allowing for some federal recognition of same-sex marriage rights.

The Transportation Security Administration's rules had not been updated when the couple flew home from Colombia on January 18, a story first reported in the Washington Blade. With the exception of husbands and wives, and parents and their children younger than 13, airlines flying into the United States from certain countries have to screen travelers individually under TSA rules.

That appears to be changing. The TSA is updating its language, an agency spokesman confirmed Thursday.

Because they were not a heterosexual married couple, American Airlines agents refused to screen Zapata and Carter together before issuing their boarding passes, Carter said. One rudely ordered Zapata back in line, Carter said.

"We knew this had happened to another couple but didn't believe it could happen to us," said Carter, a partner at the New York law office of Arent Fox.

American Airlines confirmed the two men were screened separately. Employees were following TSA security rules, said Bob Witeck, president of Witeck Communications, who consults with American on LGBT issues.

Within hours of the incident, the couple took to Twitter and Facebook to report the incident. Carter also contacted the White House LGBT liaison and two members of Congress to ask the TSA to update its airline screening questions.

"TSA is working to make clear any confusion in language included in the Aircraft Operator Standard Security Program document," wrote a TSA spokesman, via e-mail. "TSA policy is for every attempt to be made to accommodate all families traveling together." The agency declined to discuss any more specifics of its security procedures.

"I'm thrilled how quickly people decided this is wrong," said Carter. "It's a sign of the times that American executives at the corporate level wanted to stamp this out fast."

The change appears to be immediate at American Airlines, Carter said, citing an e-mail he received from an airline lawyer: "TSA has communicated to our Corporate Security folks that they are working on a technical change to its directive, and that, pending that change, we can immediately begin screening same-sex spouses together. We are working on communicating this change in procedures to our stations ASAP."

American is happy to implement the TSA change, said Witeck.

"For two decades, American Airlines has been a leader in LGBT equality, and now with DOMA's repeal, outdated rules that treat married couples differently can come tumbling down," said Witeck. "A seemingly small but crucial equality milestone for all travelers."

It won't be too long before Carter and Zapata will test the change. They have a second home in Colombia, and they're flying back in March for a wedding.

"I expect us to be treated like every other legally married couple," said Carter. "When they ask, 'Why are you together?' I will say, 'We're legally married.' We expect them to give us our boarding passes, and we'll move on."