Chris

When casting a role, it's entirely fair to see what the actors you audition might bring to it. They will have their own take on the character. You're not just casting someone who reflects your idea of the character; you are hopefully casting someone who can work on the character with you. The person you eventually cast has their own strengths and weaknesses and that will both enhance and limit what you can then do with the character.

A good current example would be Liz Carr, who plays Clarissa in Silent Witness. She has a congenital condition that, amongst other things, more or less confines her to a wheelchair. As someone who has done stand up comedy for years, I think she brings a sparkle and a confidence to the character that I really enjoy (actually I think she's my favourite character in the series). On the other hand, her mobility issues mean that in casting her, the show runners have restricted whet they can do with her. She can't go pelting off down the street like Jack or Nikki. Her appearances are normally confined to a couple of rooms within their base.

Doctor Who doesn't quite fit the usual casting rules. Normally when you have to re-cast a main role in a continuing drama, you and your audience conspire not to notice that the character's face and voice have changed. In Who, the changes in appearance and temperament that are a natural result of employing a different actor are written into the script and have an "in-universe" explanation. So yes, to answer your original point, any new actor playing the Doctor gives the script writers new possibilities. That would be the case regardless of whether the actor was male or female. However, even when selecting from exclusively male actors, the process is fraught with difficulties. Aficionados of the series generally look back on Colin Baker with affection, for example, but there's no doubt his wild, angry and sometimes murderous take on the character alienated the broader audience. And that's the key to all of this: you have to keep your audience on board. It is far from clear that casting a woman will work from that angle. The audience is used to the character being male. If they begin to feel the character has changed too much and is someone they no longer understand, they will switch off.

There will be a *lot* of audience research before they ever cast a female actor to play the doctor. No doubt in the meantime the feminist lobby will continue to complain about gender bias (while cheerfully ignoring the strange and un-feminist implications of turning 50 years of male backstory female, rather than simply building a strong female character from scratch and allowing her to stand on her own merits) but gender bias is the worst possible reason to do it. I hope that the senior people at the BBC have the good sense to see it.