Just had a v interesting chat with my dd12. Can't remember how we quite got onto it. But she told me about this YouTuber called Jazz. She is 11 but living and looking like a girl (though born male). At 7 apparently he told his parents he felt like a girl and they have gone with it. He looks like a girl and his having puberty delaying drugs, drugs that stop his testosterone, extra oestrogen. Doesn't like his genitalia.
Now maybe he is truly transgender.
But I am concerned about how much encouragement his parents were giving, how at 11 he's on major hormonal injections.
My dd thinks She - Jazz - is really cool and cute and accepts totally that a 7 year old boy can decide he's a girl.
We had a v interesting discussion where I talked about how what we think at 7 and 11 is very different to what we think at 18, 25 or even 40. Also explained the implications of the hormone treatment.
I emphasised that males and females can do anything... Girls can do - and are good at stuff seen as boy's and vice versa.
Ended up moving on to homosexuality and bisexual issues with ds9 too. My OH snuck off upstairs 
Good chat though!