In the Doctor Who episodes "The Rebel Flesh" and "The Almost People", the Eleventh Doctor (portrayed by Matt Smith) discovers that the humans of 22nd century Earth have utilized a form of programmable organic matter called the Flesh to produce Gangers: clones controlled via neural interface to perform dangerous tasks. Determining that the Flesh is indeed alive, the Doctor condemns the humans' use of it.
When a solar tsunami passes over St. John's Monastery, the Gangers of Miranda Cleaves and her team of acid miners become disconnected from their handlers, but the memories and personalities of the humans remain imprinted upon them, thus granting the clones independence. Having touched the raw Flesh prior to the solar storm, the Doctor leaves a genetic imprint upon it. When the storm hits, the Flesh forms a new Ganger in the form of the Doctor.
At first, the Ganger had some trouble adapting to the Doctor's DNA due to the residual traces of his previous incarnations in his body. These caused him to briefly act like his first, third, fourth, and tenth incarnations, which he, like the real Doctor, did not like. He stabilised into a form and manner virtually identical to the Eleventh Doctor's; the only way to distinguish them was their difference in shoes, as the original Doctor had replaced his after the initial scan. The two Doctors subsequently swapped shoes while their companions were distracted in order to prove that Gangers were no different from their originals.
Posing as his original, the Ganger Doctor tried to get Amy Pond to see there was nothing different about them. Just like the Eleventh Doctor, he knew Amy was a Ganger herself, but kept quiet.
The Ganger Doctor sacrificed himself and Ganger Miranda to stop Ganger Jennifer, setting the sonic screwdriver to a frequency that would cause the Flesh to collapse, in full knowledge that this would destroy him too, so that the others would be encouraged to negotiate better conditions for the Gangers.