The central conflict of the novel and Peter’s life is change. Change drives the plot forward, causes the growth that occurs in the characters, and illuminates the personalities behind each of them. Peter goes through the most changes of anyone in his family during this time. He is on the verge of adolescence and experiencing new emotions, freedom, and interests. He gets his first crush on a girl, has major fights with friends, lashes out at his parents, and finds his siblings intolerable. Peter is overwhelmed by the changes he is going through, both internally and externally, and struggles to cope.

When Peter learns that his parents are having a new baby, he becomes extremely angry and slams his door “so hard [his] map of the world fell off the wall and landed on the bed” (7). He cannot stand the thought of another Fudge in his life, making things harder and demanding more attention from his parents. When Tootsie is born, Peter does love her, but hates the way her presence changes the family dynamic. When his mom becomes exhausted from taking care of Tootsie and Fudge, Peter blames her, saying “that’s what you get for having another baby!” (27).