A House subcommittee hearing went off the rails Tuesday when Rep. Keith Self (R-Texas) misgendered Sarah McBride (D-Delaware), the first openly transgender person elected to Congress, and abruptly adjourned the session after a colleague confronted him.

Speaking at a hearing on arms control, international security and U.S. assistance to Europe, Self, the Republican chair of the subcommittee on Europe, addressed McBride, a transgender woman, as “the representative from Delaware, Mr. McBride.”

McBride replied to him, “Thank you, Madam Chair.”

Rep. Bill Keating, the ranking Democrat from Massachusetts, interrupted, asking Self to repeat the introduction, and Self called McBride “mister” again. “Mr. Chairman you are out of order. Mr. Chairman, have you no decency?” Keating said.

Keating went on to say the session would not continue with him “unless you introduce a duly elected representative the right way.” Self then struck his gavel and declared the hearing adjourned.

McBride said later on social media, “No matter how I’m treated by some colleagues, nothing diminishes my awe and gratitude at getting to represent Delaware in Congress.”

“I simply want to serve and to try to make this world a better place,” she added.

It is the latest affront from McBride’s Republican colleagues, who have misgendered the congresswoman on the House floor and elsewhere, as well as publicly fought against her use of the women’s restroom before she started at the Capitol. Such voices have been empowered by President Donald Trump, who made attacking transgender rights a central part of his campaign’s closing pitch and who has prioritized anti-trans policies during his first weeks back in office.

In response to Tuesday’s hearing, Self wrote on social media, “It is the policy of the United States to recognize two sexes, male and female,” citing Trump’s Jan. 20 executive order. The mandate, which narrowly defines a person’s gender, seeks to roll back transgender rights and has been criticized by some experts for overlooking the complexities of human biology.

Rep. Mary E. Miller (R-Illinois) used similar language after misgendering McBride on the floor of the House in February.

McBride’s historic election to Congress in November followed work in the Delaware state Senate that involved expanding access to health care, requiring mental health and media literacy education in public schools and promoting green technologies, according to her House bio. She’s most focused on reforming “care infrastructure,” such as passing legislation on paid family and medical leave, The Washington Post reported.

Even before she was sworn into Congress, McBride faced Republican-led efforts to alienate her. Rep. Nancy Mace (R-South Carolina) introduced a resolution in November to ban transgender women from female bathrooms at the Capitol, which Mace said was “100 percent because of McBride” and which House Speaker Mike Johnson (R-Louisiana) supported.

At the time, McBride had already made arrangements with Democratic higher-ups to use their bathrooms.

McBride’s announcement that she would follow the rules distressed some transgender people, but in a January interview with The Post, McBride said she thinks some people misunderstand “civil disobedience.”

“In this case, the disobedience is not claiming a toilet seat. The disobedience is claiming a seat in Congress and being in an institution where some people don’t want me here simply because of who I am,” she said. “The civil part is taking the indignities that come with that with my chin up.”