One of the most vehemently contested issues in modern English grammar and usage is ‘singular they’, specifically its use to refer to a person of known gender, or to someone who has chosen not to identify as a specific gender.
Over lunch, I was browsing through the Wikipedia article on Doctor Who. My eye was caught by the sentence ‘The Doctor often finds events that pique their curiosity’. Since late last year, when Jodie Whittaker took over the role, it is impossible to refer to the Doctor as he, and it was always impossible to refer to him, ummm, them as it.
The Wikipedia writer(s) use(s) they once again:
All that was known about the character in the programme’s early days was that they were an eccentric alien traveller of great intelligence
(even though in the program’s early days the Doctor was definitely he).
Alongside their in the usual plural sense:
There have been instances of actors returning at later dates to reprise the role of their specific Doctor.
there is another use of their the singular sense:
The Doctor has gained numerous reoccurring enemies during their travels.
On the other hand, the Wikipedia writers also use he/him/his to refer to a specific incarnation of the Doctor pre-Whittaker, for example:
the Fifth Doctor [played by Peter Davison] explicitly confirmed that he was then currently in his fifth incarnation
He [the War Doctor, played by John Hurt] is shown in mini-episode “The Night of the Doctor” retroactively inserted into the show’s fictional chronology between [Paul] McGann and [Christopher] Eccleston’s Doctors, although his introduction was written so as not to disturb the established numerical naming of the Doctors.
On the other other hand, there are no references to the Doctor as she/her/hers (yet).
What the Wikipedia writer(s) write(s) is not necessarily canon. The BBC might or might not have thought about the issue.
The reason I was browsing through the Wikipedia article was that I had pretty much randomly chosen from my bookshelf, for light reading, a book about Doctor Who subtitled “His Lives and Times”. This was pre-Whittaker, indeed pre-Peter Capaldi; the current actor was Matt Smith, and his photo is featured prominently on the cover. Maybe the next edition will be “Doctor Who: Their Lives and Times”.