Of course, this would leave Doctor Who without a female presence on the show…unless the Doctor were to change gender too, of course.
Even showrunner Steven Moffat has spoken about it before, saying it could happen in the future since you cast a person in the role, not a gender.
I think it would be damaging to Doctor Who if that voice and viewpoint were not represented.”
Broadly speaking, Doctor Who is a show that ticks along nicely, never really causing too much controversy… until the subject of gender comes up, that is.