Why women can't be Doctors

Monday's Guardian has an interview with Russell T. Davies (tucked away for some reason in the Media section). It contains few surprises, but this pair of paragraphs had me boggling:

He is not a man to shy away from controversial comments, and says Tennant's eventual replacement should not be female. "I am often tempted to say yes to that to placate everyone but, while I think kids will not have a problem with [a female Doctor], I think fathers will have a problem with it because they will then imagine they will have to describe sex changes to their children.

"I think fathers can describe sex changes to their children and I think they should and it's part of the world, but I think it would simply introduce genitalia into family viewing. You're not talking about actresses or style, you're talking about genitalia, and a lot of parents would get embarrassed."

I used to cherish the hope of seeing Miriam Margolies take over the rôle, and I'd come to terms with the fact that it wasn't going to happen. But as reasons go, that's bad one. "Because I don't want to," works better.

But no, Russell T. would love to. It's just that all the dads (who explained Captain Jack without blushing) begged him not to embarrass them. They have no trouble explaining time paradoxes, and the Doctor's general ability to regenerate is child's play.

But it seems that when the Doctor regenerates into a whole new person, new body, new personality, new style, new mannerisms, there is actually one part of him that doesn't regenerate, one small but important part that stays constant...

Do I believe this? No, I think it's a load of genitalia.