I would love a female doctor, but I think in general I would just love more strong female actresses anyway. One example is I just finished watching Season 1 of Orphan Black. Before this show, I had no idea who Tatiana Maslany was, nor did I know anything about the show. 10 episodes later I want her to be nominated for 2 Emmy awards for best actress (Sarah Manning) and best supporting actress (Alison Hendricks). She was that great and it was an absolute thrill to watch her work, and be a strong female actress in a format that is dominated by male actors. Find another Tatiana-type actress to play the doctor and you don't have to worry about casting the Doctor a female actress because of the whole sexist thing. Let the work speak for itself.