While fans thought it was dismissed with an offhand joke a few years ago, current "Doctor Who" show runner Steven Moffat says he's sticking by the rule of continuity established on the show in the 1970s - that The Doctor only has twelve regenerations available to him.
Speaking at the Cheltenham Literature Festival over the weekend, Moffat confirmed the rule, and teased: "I think you should go back to your DVDs and count correctly this time. There's something you've all missed."
Peter Capaldi takes on the role shortly, playing the apparent twelfth incarnation of The Doctor which would mean he has one more regeneration available. Of course, the upcoming 50th anniversary special and how it shakes out may change that count - especially when the true nature of John Hurt's incarnation is revealed.
Writers for the show have always found a way around the rule when needed - The Master possessing another person in "The Keeper of Traken" and later getting a new regenerative cycle. The regeneration count could also be off due to other incidents - the Tenth Doctor's stalled regeneration in "Journey's End," River Song's use of her remaining regenerations to heal The Doctor in "Let's Kill Hitler," and the "offscreen" regenerations of two previous Doctors.
The question of course isn't that a workaround will be reached, the question is how and when. Will Moffat bring it up in the upcoming specials or Capaldi's early episodes - or will he shift the burden to whomever next takes on the producing reigns of the show?
Source: The Live Feed