We have seen / been told that Gallifreyans regenerate into a different sex before too - The Corsair or The Master/Missy for example…
There’s that tired excuse again. This “precedent” was created after Moffat was accused of sexism and the new fangirls started demanding a female Doctor. Since then to combat that image he kowtowed and started to introduce those elements. Nowhere in the classic series is something like this hinted at. If NuWho can’t get the Doctor’s age right, I’m certainly not going to trust it with something like this.
I’ll be watching the Christmas Special and first episode of series 11 but will probably be stopping after that. I would not be surprised to see the show’s ratings start to drop after this.