I'm giving you all a fair warning, there are spoilers ahead for anyone who isn't caught up on the latest episode of Doctor Who! Proceed with caution, all yee who enter here.
At long last it is becoming more likely that the next iteration of the Doctor could be female! Since learning that Missy (short for Mistress) is actually the Master, it would appear that the long-discussed possibility of switching genders during regenerations has proven to be not totally uncommon on Gallifrey.
The longtime showrunner, Steven Moffat stated in an interview with Wales Online (via International Business Times), in regards to the Doctor's reaction to the Master's return:
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.
Quite fluid, eh? To me that sounds like there's now background that would validate finally making the next Doctor a woman. If it worked for the Master, then why not the Doctor?
The current Doctor, Peter Capaldi furthers the discussion of Missy and the Doctor in an interview with SFX (via GamesRadar):
I think with Missy that was just a great idea...You wanted to keep it a surprise and that was the best way to do it, but yes, it does suggest all kinds of interesting stuff. They have a total love/hate relationship anyway but they were both men for a long time, and still have that love-hate relationship, and we will see more of that probably. It’s interesting, being able to swap like that. I think it’s good.
Not that I'm at all ready to see Capaldi go, but now that we know that it can happen, will it actually happen? What's the likelihood of this actually going down? Well, according Peter Capaldi, there will and we might not be too far away:
There easily could be a female Doctor...I think the next time might be a female Doctor. I don’t see why not. I think it’s good to do that.
As a female Whovian, the mere discussion of this gets me really excited! While there have been some pretty strong and opinionated female characters (holla Donna Noble and River Song!), the last two companions especially have been almost too devoted to the Doctor.
Hell, I loved Amy Pond but she was literally called "The Girl Who Waited." Because that's exactly what she did. She would sit around and wait for the Doctor, on multiple occasions, while her life kind of just happened around her.
For that reason, it would be nice to see some diversity in the female cast. We're usually relegated to the roles of either "devoted, lovestruck companion" or "evil villain mastermind." That's not to say I don't like being compared to a mastermind, evil or not, just not all the time in my favorite show.
That being said, I think that more diversity in the main Doctor Who cast would be great overall. Sure, one of the most common guest stars is the lesbian Silurian assassin, Madam Vastra, so that's pretty diverse. But I'm also still waiting on a black Doctor, or any sort of non-white Doctor, really. He's a freakin' Time Lord from Gallifrey! He could essentially be any combination of gender, race, or sexual preference in the universe.
At the very least the show could bring back a classic Time Lord like the Rani. Yes, she was an evil genius and a renegade Time Lord, but we had already met the Master. I realize it's too late now, but having Missy be the Rani would have been a pleasant surprise that would have brought back old favorites and added some diversity. A win win in my book.
While we're at it, as commenter Sam Kelley-Mills pointed out, they should throw more male companions too! In the rebooted series Rory, Mickey, and Danny have all been brought onto the TARDIS by association. Probably the only exception to this would be Captain Jack Harkness, and even then he wasn't really a constant or one-on-one companion. It's hard to believe that a show that has been on the air for this long, and invests so much time on portraying the future, is not more progressive in these areas.
In the end, I'm most partial to the actor who is best for the role, regardless of gender or skin color. But there are plenty of actors of all shapes, sizes, and colors that I'm know would make a great Doctor, so maybe we should go forth with that idea in mind for the next round of casting.
Still the most pertinent question remains, will the Doctor finally have red hair?