Marta Kauffman is looking back on things she wishes she’d done differently on “Friends”.

The series co-creator sat down for an interview with BBC World Service’s “The Conversation”, set to air on July 11, and she shared her regret about the portrayal of Chandler’s transgender parent.

READ MORE: ‘Friends’ Co-Creator Marta Kauffman Blames ‘My Own Ignorance’ For The Show’s Lack Of Diversity

In the sitcom, male pronouns were used to refer to the character’s parent, portrayed by Kathleen Turner.

“We kept referring to [Helena] as ‘Chandler’s father’, even though Chandler’s father was trans,” Kauffman said, according to “Pronouns were not yet something that I understood, so we didn’t refer to that character as ‘she’. That was a mistake.”

In the years since, Kauffman’s approach on trans issues has changed in big ways, particularly when it comes to running a set.

“I like very much to create an environment where we have a happy set and a happy crew,” she said. “It’s very important to me that where we are is a safe place, a tolerant place, where there’s no yelling. I fired a guy on the spot for making a joke about a trans cameraperson. That just can’t happen.”

READ MORE: ‘Friends’ Co-Creator Marta Kauffman ‘Embarrassed’ By The Sitcom’s Lack Of Diversity; Pledges $4 Million For African Studies

Kauffman, who most recently co-created the Netflix hit “Grace and Frankie”, has also recently addressed criticism of “Friends”‘ lack of diversity and representation for Black characters, leading her to pledge $4 million to African and African American Studies at Brandeis University in Boston.

She said the donation came out of “guilt” she felt over the show’s contribution to “systemic racism” in the industry.

“Over the course of the last few years I’ve gotten to the point where I can say unfortunately yes, I am guilty of that. And I’ll never make that mistake again,” she told the BBC. “I was clearly part of systemic racism in our business. I was unaware of that, which makes me feel stupid. That was a very valid, extremely difficult criticism which still… I get emotional about.

Kauffman added, “If I knew then what I know now, there are certain things I would have changed. But I didn’t know them and I have since learned.”