Maybe, Baby

S3, E1: Jill's sister Carol is having a baby girl. When they talk about the baby's name and Jill is going through the boys' baby toys, she wishes she could have a baby girl. Tim tells Randy and Brad that Jill always wanted a girl so they tell Mark that Jill wished he had been a girl. This upsets Mark and when Jill wants to bake a cake with him, he doesn't want to.