A House Foreign Affairs subcommittee hearing ended abruptly Tuesday after Rep. Keith Self (R-Texas) referred to Rep. Sarah McBride (D-Del.), the first transgender person elected to Congress, as “mister.”

Self, who chairs the subcommittee on Europe, introduced McBride as “the congressman from Delaware” during a hearing on arms control and U.S. assistance to Europe. McBride responded by calling Self “Madam Chair.”