Bruce Jenner's family has been very supportive of his alleged transformation from male to female, but Kourtney Kardashian is reportedly worried about how she will tell her young children. A source told Radar Online that while Kourtney and her boyfriend, Scott Disick, have accepted Jenner's decision, they have no idea how they should break the news to Mason, 5, and Penelope, 2.

"The whole family is supportive of Bruce's transition," the source said. "But Scott thinks it is going to be a little weird to have to explain to the kids what is going on."

"They're too young to understand," the source continued. "As of right now, Bruce is 'Pop-Pop' to Mason and they do not know how they are going to tell Mason [that] Bruce is going to now be a grandma. Penelope is at that age where she will not remember Bruce as a man. [The same thing] with Reign. But Mason is so inquisitive and nothing gets by him."

It's been reported that Jenner will address his alleged transformation during an interview with Diane Sawyer and on Season 10 of "Keeping Up With the Kardashians." He's also filming his journey for a docu-series to air on E!.

"Kourtney and the kids love Bruce," the source told Radar. "He has taken good care of them and has spoiled Kourtney and the children rotten as long as he's known them. They'll figure it out."

Another family source told People magazine that when Jenner finally came out as transgender to his children and step-kids, many of them weren't surprised. The source said initially Kim Kardashian was worried about her mother, Kris Jenner, and wanted to know how she was emotionally handling the news.

"Bruce told them everything - where things stood, what his plans were for the future, and what everyone could expect," the source said. "Everyone basically knew what was up, but it was still a shock to hear it outlined so explicitly."

Kim's husband, Kanye West, took the news in stride. The source told People that the rapper is "totally fine with it" and is just trying to show Jenner "love and acceptance." Disick, on the other hand, reportedly "didn't react very well" to Jenner's revelation, but has now come around.