The Doctor (Doctor Who)
The Doctor is the title character in the long-running BBC science fiction television programme "Doctor Who". Since the show's inception in 1963, the character has been portrayed by thirteen lead actors. In the programme, "the Doctor" is the alias assumed by a centuries-old alien—a Time Lord from the planet Gallifrey—who travels through space and time in the TARDIS, frequently with companions. The transition to each succeeding actor is explained within the show's narrative through the plot device of "regeneration", a biological function of the Time Lord race that allows a change of cellular structure and appearance with recovery following a potentially fatal injury.
List of actors considered for the part of the Doctor
When referring to if the new Doctor would be a woman, incoming "Doctor Who" showrunner Chris Chibnall originally was quoted in February 2017, as saying "Nothing is ruled out but I don’t want the casting to be a gimmick and that’s all I can say”. 
The role of the Thirteenth Doctor went to Jodie Whittaker, the first woman to play the Doctor in the television series. She had previously worked with Chibnall in "Broadchurch". Chibnall said that he always wanted a woman for the part and that Whittaker was their first choice. Whittaker has said that other actresses auditioned for the part.