NEW YORK - Kris Jenner, the matriarch of the Kardashian-Jenner reality television tribe, says she did not know of her former husband Caitlyn Jenner's gender struggle.

In new excerpts from the Vanity Fair July cover story introducing Olympic gold medallist Bruce Jenner as Caitlyn, Kris said of the twilight of the couple's 24-year marriage: "He was married to me, and he wasn't who he wanted to be, so he was miserable. It was the most passive-aggressive thing I think I've ever experienced."

She added: "Why would you want to be married and have kids, if this is what you wanted since you were a little boy? Why would you not explain this all to me?"

Kris, 59, has six children from two marriages. Her daughters with Caitlyn, 65, are Kendall, 19, and Kylie, 17.

The former couple had got together after going on a blind date when Kris was finalising her divorce from lawyer Robert Kardashian in 1990, said The New York Times Magazine. The Jenners finalised their divorce in December last year, before Bruce announced his transition to life as a woman in April.

Buzz Bissinger, the reporter who spoke to them for the Vanity Fair article, said he believed Kris Jenner, who was "very civil" and "very open" during the interview.

He said on the Today show on Tuesday: "She says, 'I didn't know. I had no idea about the extent of his gender issues.' And I got to say, I think she's right. Bruce downplayed it, said, 'It was a phase of my life, it's over.' But it wasn't over."

In the new excerpts from the Vanity Fair story, Kris and Caitlyn Jenner could not agree on how much the ex-wife knew of the ex-spouse's desire to be a woman.

Caitlyn said Kris knew her former partner had taken hormones in the 1980s, with side effects including B-cup breasts.

But Kris said that though they had a conversation about the hormones, "nobody mentioned a gender issue" and "he never really explained it". She added that her ex-spouse had a "little bit of a man-boob situation" but "no B cup".

Caitlyn said Kris had seen her former partner wearing women's clothes, adding that they had an agreement that Caitlyn would cross-dress only when she was travelling alone.

But Kris said she had not caught Caitlyn in a dress, though someone mentioned Caitlyn "at one point in life liked to dress up".

Back in April, Caitlyn had said she "would probably still be together" with Kris if she could have been understanding of Caitlyn's transition.

But she told Vanity Fair a different story of their split. "Twenty per cent was gender, and 80 per cent was the way I was treated," Caitlyn said.

She added that Kris "wasn't very nice".

She felt Kris became "less tolerent", after getting credit for the success of the family's reality show Keeping Up With The Kardashians. "People would see how I got mistreated. She controlled the money, all that kind of stuff."

Caitlyn also explained her new name. She watched the Miss America pageant for ideas, and liked names including Heather and Caitlyn, said Vanity Fair. She chose Caitlyn after her assistant also suggested it.

Caitlyn decided to spell her name with a C, not a K, to break with the Kardashians' tradition, said the magazine.