In this clip from the episode, Kylie asks Caitlyn about having children and they get on the subject of her and Kendall Jenner.
"What do you feel like is a good age to have kids?" Kylie asks. "Like 25."
"30's a good age," Caitlyn says. "30's a good age."
"I feel like 30's too late," Kylie tells Caitlyn. "Every psychic said I'm only gonna have two kids."
"When you have one you might as well have two," Caitlyn says. "And you want your kids close together, that's why we had you. Might as well have the two so they have somebody to grow up with."
A shocked Kylie responds, "Oh OK! So I'm just..."
"Somebody for Kendall to grow up with," Caitlyn says.
"I'm the one to keep Kendall company," Kylie laughs.
"Yeah," Caitlyn says.
Caitlyn then goes on to tell Kylie she has to have "at least 3" kids so she can have 30 grandchildren!
Check out the video above to see Kylie's reaction!
Watch a brand new episode of Keeping Up With the Kardashians Sunday at 9 p.m., only on E!