The former ‘Keeping Up With The Kardashians’ star sat down with Piers on his ITV chat show and talk turned to her transition.
In the interview, which airs on Thursday (3 January) night, the ‘Good Morning Britain’ presenter asked Caitlyn a question about her body.
Holding a figurine of Caitlyn during her Olympic days, when she was living as Bruce Jenner, Piers said: “How does your physique compare now to what is was then? Obviously certain areas we know...”
But Caitlyn was having none of his comments, saying: “You made a comment there and that’s why you would get in trouble, OK? You said, ‘certain areas’ - that, to a trans-person, is disrespectful.”
As he smirked and asked why he “couldn’t make a joke” about it, Caitlyn responded: “Because it’s not funny. It’s life. It’s a very serious part of my life.”
Piers went on to press on whether “life could be funny”, but she continued: “I take that very seriously and so out of respect to myself and the community, it’s not something that you joke about.
“As I said before, this is serious stuff. People die over these issues. It’s not a joke.”
Piers seemed to have been persuaded by Caitlyn’s argument, conceding: “It is educational. It is. It is a complex issue.”
During the interview, Caitlyn also revealed she no longer has contact with her Kardashian step-daughters.
“Yeah. I don’t talk to them anymore,” she said. “Actually the day before I left to come here Kendall had a party and I went.
“I had not talked to any of the kids on that side. Kris, [it’s been] probably a year and Kim about nine months and Kourtney I have not talked to them either.
“It was a little uncomfortable. I called Kendall the next day and said, ‘You know what it was a good ice breaker’. The only ones I am concerned about are Kendall and Kylie. They are my biological kids. I spent 23 years carting them around.”
‘Piers Morgan’s Life Stories’ airs on Thursday at 9pm on ITV.