“I worried, out loud, in print, once or twice, back in the old days, about the reaction to a female Doctor.But d’you know what? That was 13 years ago. 13 long years. I’ve grown up, and learnt, and I hope I know better, and the world has grown up too.”
http://www.radiotimes.com/news/tv/2018-04-11/russell-t-davies-says-hes-grown-up-after-worrying-about-casting-a-female-doctor-in-doctor-who/
http://www.radiotimes.com/news/tv/2018-04-11/russell-t-davies-says-hes-grown-up-after-worrying-about-casting-a-female-doctor-in-doctor-who/