The Family Circus is a syndicated comic strip of family life created by cartoonist Bil Keane and currently produced by his son, Jeff Keane.
In "Dog Gone", Brian chastises Bill, the Family Circus father for giving him plain advice and suggests for him to have sex with his wife, which he obliges. Later Peter is reading the paper and finds the edition of the comic very shocking.
While trying to track down Stewie after he runs away in "Hot Shots", Brian and Lois observe a trail, but finds that it leads to oldest son Billy, who has died of measles.