Right, I'm back although I don't know that I have much sense to share.
@bonbonours Our daughter is 14 as well. From reading other threads on here, Yr9 seems the peak stage for this to happen. What was the social contagion for her? Here, interestingly, it seems to be in school rather than the internet, as we've mostly peeled her off her phone without complaint, but half the class showed up at the online Pride group this week.
@persistentwoman My next job is to see whether the Cornwall guidelines still meet the DofE recommendations now. I suspect not. If anyone knows any links or guidance, that would be really helpful.
@MondayYogurt and everyone else. Yes, basically. I'm at a very early stage of understanding - assimilating lots of information and putting it together logically for non specialists is basically my job and so I am dealing with this via the means of research. But there do seem to be a number of factors which predispose to rapid onset gender issues in teenage girls and a big bust is definitely one of them. Also mentioned in despatches are non-neurotypical (she has ADHD, rather than the ASD which is extremely common), and being gifted, which DD also is. So in short, she feels really different, and this is a convenient outlet.
I think this desire to get out of the pressures of gender and sex is nothing new. I was a fat goth at 16 - and felt different for a whole host of other reasons including being a southerner in Manchester and arriving at a new school in Yr 10 with 4 GCSEs already. I didn't have a hope. But what I observed even then was that female goths were either fat girls who didn't want to be judged by conventional standards, or were extremely pretty and frightened by their attractiveness.
Meanwhile my friend at university was very attractive and spent the second year basically dressed as non-binary in loose jeans, leather jacket, wooly hat, spiked short hair. Just like any non-binary girl now, but without the language to call it that. She also had a pair of dungarees, which were pale brown and made out of sweatshirt fabric, with a crotch which hung down to her knees. Everyone else couldn't understand why she wore it; I knew exactly why, because she wanted people to see her mind (we were at Cambridge fwiw).
So I do understand. But I don't think - as you've said - that any of this is feminist. Go and be who you are but as a woman. But then can you change the prison of gender when you are 14, on your own?