This seems to be a common thing now with each Doctor regeneration but it never makes sense.  Yes, Moffat tossed in that the Doctor knew someone who went from male to female, but again, it was very quickly tossed in there.

What many new Doctor Who fans do not seem to know is there are Timelords and Timeladys.  Taking a look at the fourth Doctor era it is clear he traveled with a Timelady: Romana.  She’s a great character (both regenerations).

Look at that, a Timelady and Timelord, they don't seem to be having any issue with it

Look at that, a Timelady and Timelord, they don’t seem to be having any issue with it

For the most part she’s more competent than the Doctor and their chemistry reflected this.  At one point, Romana made a better sonic screwdriver than the Doctor and he tried to take it but failed in doing so.  Importantly, during her regeneration, Romana went through a few bodies, all of which were female.  This regeneration process helps show how there are in fact male and females from Gallifrey.

I’m all for strong female leads.  Currently I’m loving Orphan Black, which if you don’t know is about a group of clones, all female and played by the same actress.  The characters in Orphan Black are all unique and strong, making their own decisions and having to deal with the events unfolding around them.  If Doctor Who wants to have a female lead then why not bring back Romana?  I’m sure there could be a cool plotline in which she has to save the Doctor because he’s gotten himself in a mess of some sort.  Since she’s a Timelady she’ll be able to do all sorts of Doctor-ish things but still maintain the continuity of the show and respect the history of it (something Moffat says wants to do but does very poorly).

I’m going to keep this post short because any more and it will turn into senseless rambling.  Just know, the Doctor should remain a male since the show, for pretty much every year prior to Moffat, has had Timelords and Timeladys.  Also, the Doctor is a grandfather, so would the Doctor then be a grandmother as well?  Moffat has tendency to mess up the show, but to ruin so many years of continuity would almost be unforgivable.