Ooh, I just had a thought.
When we eventually get a female Doctor, there could be quite a nice scene early on in their run…
ALIEN: And what’s your name?
DOCTOR: Oh, John Smith.
DOCTOR: Did I say John? Joanna, I meant Joanna. John, short for Joanna. Without the “an” and the “a” parts, obviously. It’s a family thing you see, John and Joanna… Yes. Joanna Smith, that’s me.
It’d just be a nice way to show the Doctor adjusting to the change. (Assuming that’s the way they want to go with it, of course, that’s hardly necessary.)