I've always been very comfortable with my gender but I didn't Really Like being a woman until I cut my hair short and started dressing/presenting more "masculine."

In this episode, there's a throwaway line (it gets expanded upon in a novel, apparently) implying that she is transgender. And perhaps I'm reading too much into RTD's intentions here, but in neither that episode nor any of her repeat appearances, her gender is never denied.

What she is denied is humanity, on the basis of having had so many surgeries to keep herself looking "young and pretty" that she is just a flap of skin with a face stretched across a rack. That's not even subtext, that's just text, Rose has a brief monologue about it towards the end of the episode.

And there's something so deeply unexamined there, about how surgery to change your gender is fine and morally neutral, but anything else that modifies your body is Unnatural and Bad and makes you Less Human.

how do you distinguish grey from other colours beyond black and wite?

Distinguishing features of moral beige:

The protagonist is constantly agonising over Hard Choices; however, circumstances always conspire to prevent them from actually having to make those choices, so in practice they're just angsting over stuff they might have done.

The text exhibits a recurring pattern whereby the protagonist seems to to have made a Hard Choice, but new information is reliably revealed shortly thereafter which retroactively establishes that whatever they did was the morally upright course after all.

The protagonist's moral impulses are straightforwardly heroic, except in one specific context which lacks any clear real-world analogue; for example, being prejudiced against telepaths.

The protagonist's actions are consistently reasonable based on the information available to them – they're merely operating on bad information basically all the time due to a bizarre conspiracy and/or a series of increasingly implausible misunderstandings.

I still remember being annoyed whenever The Doctor was going to have to make a hard choice or do some heroic sacrifice, but then someone else does it instead. Really thinking of the resolution of the one arc with the sontarans making like, evil car air conditioner or something. He was threatening to blow himself and the ship up, but then the former antagonist swaps places with him and does it. And it saves the doctor from having to face any loss, and from having to figure out what to do with that fucker.

Next up someone is going to claim that the Narnia series isn't kids books.

She is fine, to be clear. But she knew she'd be missing it, because of surgery, when she made that tweet.

Look I don't have a whole tag of 'hubris is a coward's word' for nothing.

Anyway 99% of humanity's evolutionary and civilization success comes down to using tools and prostheses for things most animals need to rely on natural attributes to accomplish at all. There's a spectrum that starts with clothing and cooking fires and ends with disembodied brains and remote-controlled drone bodies, and any bright line you draw on it about where 'human' stops is going to be more or less arbitrary.