ET have reported that Caitlyn Jenner, 68, wasn't thrilled about her daughter becoming a mum at a young age.
A source revealed Caitlyn "wasn't happy at first about Kylie becoming a young mother."
As for mum-to-be Kylie, she "wasn’t happy about how Caitlyn responded."
However, Kylie has always been open about wanting to be a young mum.
In 2015, a 17-year-old Kylie said she wanted to have children early.
"When I look to the far future and decide to have kids, I need to have a million girls," Kylie told Teen Vogue. "Ten years from now -- in 2025 -- I hope I have a kid."