Corin

Aka the Human Metacrisis Doctor. He looks like the 10th Doctor, but he is mostly made of Donna's DNA (SOURCE: My arse)[citation sneeded]. Rumour has it that he is truly a eunuch. (see image)

Rose insisted that she wouldn't keep referring to him as the Doctor. The meta-crisis Doctor decided to give himself a new name, eventually choosing the name "Corin", a name that Rose considered to be "solid and true". (PROSE: The Turning of the Tide) However, he would continue to be addressed as "the Doctor" by others. (AUDIO: The Siege of Big Ben, Flight Into Hull!)

It is important to note that only Judy calls him "Corin". Don't be a Judy.