Caitlyn Jenner wants 30 grandchildren, and she needs Kylie Jenner's help to get there. In a sneak peak clip from this Sunday's episode of "Keeping Up with the Kardashians," Caitlyn and Kylie had the baby talk - all while in front of her boyfriend Tyga!

"What do you feel like is a good age to have kids?" Kylie asked her dad. "Like 25?"

"Thirty's a good age," Caitlyn told her daughter. "Thirty's a good age."

"I feel like 30's too late," Kylie told Caitlyn. "Every psychic said I'm only gonna have two kids."

Caitlyn then explained that if someone was going to have a single child, they might as well have another and revealed that's what she and ex-wife Kris Jenner did with Kylie and her older sister Kendall Jenner.

"Oh, OK! So I'm just the one to keep Kendall company," Kylie said in mock outrage.

The "I Am Cait" star then told her daughter and her boyfriend that she wanted at least 30 grandchildren and that Kylie needed to have "at least three" kids if that were to happen.

"You want 30 grandchildren?" asked Tyga, 26.

"Thirty grandchildren I think would be perfect," Caitlyn replied.

While Tyga remained mostly quiet during the conversation between Caitlyn and Tyga, the rapper revealed on Khloé Kardashian's new talk show "Kocktails with Khloé" that he wanted to marry Kylie, as HNGN previously reported.

"Keeping Up with the Kardashians" airs Sunday's at 9 p.m. EST on E!

Check out the full clip below: