Look Who's Talking Too(1990)

Mikey’s back and about to face his greatest challenge… his new sister.

Mollie and James are together and raising a family, which now consists of an older Mikey and his baby sister, Julie. Tension between the siblings arises, and as well with Mollie and James when Mollie's brother Stuart moves in. Mikey is also learning how to use the toilet for the first time.