Bartholomew "Bart" Simpson is voiced by Nancy Cartwright (that's right, a woman!) and is Homer and Marge's only son on The Simpsons. Bart is an underachiever and was definitely much more of a bad boy in th ebeginning seasons of the show.
Now, Bart, although he has not aged, has certainly matured as a character. Do the Bartman people.
Bart: Boys and girls, Mrs. Krabappel, I come before you today to solve a riddle that has plagued mankind for centuries: What has four legs and ticks?
Milhouse: A walking clock?
Nelson: A walking clock!
Martin: I'd wager he has some variety of walking clock in that box!
Edna: Bart, is it a walking clock?
Bart: What?.....No, it's my dog.
Bart: Take him away, boys.
Chief Wiggum: Hey, I'm the chief here! Bake him away, toys.
Lou: What'd you say, chief?
Chief Wiggum: Do what the kid said.