After pledging $4 million to Brandeis University over “guilt” about the lack of racial diversity on “Friends,” co-creator Marta Kauffman is now expressing regret over how the show represented another demographic: transgender people. In an interview with The Conversation on the BBC World Service that will air on July 11, Kauffman called it a “mistake” to refer to the transgender mother of Chandler Bing (Matthew Perry) as his “father.” “Pronouns were not yet something that I understood,” Kauffman told the BBC. “So we didn’t refer to that character as ‘she.’ That was a mistake.’” The character, who had the stage...