Question: is ralph not chief wiggum's son?
Answer: Turns out that Ralph Wiggum was not canonically made to be Chief Wiggum's son until season 4. ... The staff figured that he'd also fit perfectly as the son of Chief Wiggum, a fact made canon in “I Love Lisa”, (although he is referred to by his last name of Wiggum in “Kamp Krusty” before).