Master Race

The Master Race were created when The Master stepped into the Immortality Gate.

Biology
The Master was the leader of the race, although everyone else was exactly the same as him. Therefore no one disagreed with him. Each was identical with no differentiation in gender.

History
When the Master stepped into the Immortality Gate it sent out his genetic structure to every human on Earth to turn every one into exact copies of him. The Master discovered two humans had escaped this fate, Donna Noble and Wilfred Mott. Donna called Wilfred to ask why everyone had changed. The Master then commanded everyone in the area of the call, after having it tracked, to bring her to him. They were all knocked out as Donna's defense mechanism, left in her mind by the Doctor, kicked in. After the Doctor escaped, The Master commanded all of the Masters who took over people of high military power to get ready all missiles and to search for The Doctor.

After the Immortality Gate was destroyed, The Master's genetic code was removed from the human race by Rassilon, bringing them back to normal.