Dexter, AKA Boy Genius is a unique boy with a giant laboratory behind his bookshelf, and invents machines, chemicals, and robots. He is always battling his rival Mandark and his older sister, Dee-Dee.
From 1995-2001 of Dexter's Laboratory, and in "Dexter's Ego Trip", Dexter was voiced by voice actress, Christine Cavanaugh, who won an Annie Award for her performance. She left the show in 2001 after her retirement from voice acting.
From 2001-2003, and in most current media, Dexter is voiced by Candi Milo, who gives Dexter a noticeably more high pitched voice.
For the video game, "Cartoon Network's Punch Time Explosion", like most of the voice cast, Dexter's voice was replaced with a sound-a-like. Tara Strong takes over the character for this game.