Astro Boy: Tetsuwan Atom - episode 11 - 14 Jun, 2003

Atom and Dr. Ochanomizu visit the town of Bellanotte, where they see a robot circus. Atom then realizes that there is a human boy among the robots. The boy, Reno, was an abandoned child raised by the robots. When Reno tells Atom that he will be separated from everyone if the truth gets out, Atom promises not to tell anyone. However, the town's don, Gustav, who is an enemy of the robots, finds out Reno's secret, makes up a story that the robots have kidnapped the child, and tracks down the robots to dismantle them. (Source: Wikipedia)