if someone is deliberately attention seeking, you really need to ask why? There is usually some inner turmoil, so attention seeking in and of itself is often just a cry for help.
I've mentioned this before on such discussions, but it's relevant:
At 11-12, DS was deeply, almost suicidally unhappy with who he was, and did indeed say to his GP that he hated himself and wished he was a girl. We were very lucky, in retrospect, that he was just about young enough not to have much access to social media, and that the CAMHS professional who saw him listened to him carefully and then said, in no-nonsense fashion, that he had neither a gender problem nor a mental health problem but a school bullying problem: he was being ostracised and called gay, girly, wimpy, weirdo...
He moved schools. It seemed a huge upheaval and over-reaction, to a lot of our friends, but by god it was less of one than having him well-meaningly encouraged down the route of gender transition.
And an even moderately pro-transition professional could so easily have looked at him and thought it was a clear-cut case - shaggy curls, dainty face; history of dressing in bright, flamboyant, silky clothing (including tutus, of course); love of reading, dancing, singing, cooing over baby animals; preference for avoiding football and playing with his female cousins (while wearing their clothes and hairclips) - I've seen pretty much this exact history online as leading other kids to transition.
He's late teens now: flamboyant, happy, into musical theatre, has a terrific hat collection, loves shopping, has had a couple of teenage relationships (boy-girl: he's not even gay).
He can't be the only one.