They had a female time lord in the Tom Baker era, Romana, so nothing new about a time lady. It does seem to screw with the character too much for my taste to have him go transsexual with regeneration. Not that it matters as I was turned off already by the other pervert crap like the queer assistant who was hitting on The Doctor and Rose at the in succession. I will keep watching my campy 60s-80s era Doctor Who.
The actress who played Romana 2, Lalla Ward, was married to Tom Baker, for 16 months, and has been married to Richard Dawkins (yes, that Richard Dawkins), for the last 20 years.