Kim Kardashian explains in a preview for Sunday's episode of I Am Cait why her family was upset by some of the things their stepdad Caitlyn Jenner told Vanity Fair magazine.

Kris Jenner married Bruce Jenner in 1991. They have two adult daughters Kylie and Kendall Jenner -- and a reality TV empire -- but split up in 2013. Their divorce was finalized early this year after which Bruce came out as transgender in a Vanity Fair cover story and is now known as Caitlyn.

"Khloé sees my mom upset and so she gets defensive," Kim said about her sister before Caitlyn interrupted, "And she doesn't know anything about my side of the story."

"But, that's what kids do," Kim explained. "She is gonna get defensive."

"The Vanity Fair article was very interesting for me to do because it was the first time I ever really had the opportunity to be absolutely truthful with a reporter about every aspect of my life," Caitlyn continued.

"I read the Vanity Fair, as well, and I think there are some things that you said that you might not realize are hurtful," Kim noted. "You said Kendall and Kylie Jenner were a distraction, and so when they read that, they're gonna think -- I don't think they'll quite understand that. Then it said, 'Had Kris been accepting to who I am, we still would be together.' And that's the most unfair thing in the world to say."