Spoilers for Doctor Who Season 8 finale.

Fans of Doctor Who may finally see the titular character regenerate into a woman. Showrunner Steven Moffat and 12th Doctor Peter Capaldi have both indicated that the recent female incarnation of the Master has opened up the possibilities for a female Time Lord.

During the season finale last month, it was revealed that the Doctor’s long time adversary, The Master, has regenerated into a woman known as Missy (Michelle Gomez). Moffat pointed out to Wales Online that Capaldi’s Doctor showed no surprise when the Master returned in female form.

“He doesn’t seem to register the fact that his old friend is now a woman. So obviously, he doesn’t think it’s a remarkable thing to happen. We must assume that gender is quite fluid on Gallifrey,” said Moffat. He goes on to say that a female doctor has been a possibility since he took over as showrunner in 2008.

Peter Capaldi, who has just taken over the role of the Doctor this year, believes that the next incarnation of the character should be portrayed by a woman. “There could easily be a female Doctor,” said Capaldi to SFX, “I think next time might be a female Doctor. I don’t see why not. I think it’s good to do that.”

Capaldi really supported the idea of the Master coming back as a woman. “They have a total love/hate relationship anyway, but they were both men for a long time and still have that love/hate relationship,” said Capaldi, “And we will see more of that probably. It’s interesting, being able to swap like that. I think it’s good.”

The idea of a female Doctor is not a new concept. Tom Baker introduced the idea to fans in the 1980s and Matt Smith, Capaldi’s predecessor, wanted his successor to be a woman.

If Capaldi’s successor does  turn out to be a woman, fans won’t be seeing her until at least 2016. Capaldi is set to return as the character in the 2015 season of Doctor Who. Fans will see him next in the upcoming Doctor Who Christmas special Last Christmas.