It's very sad that adolescent/ teen girls seem so ill equipped to transition into womanhood let alone into a different gender.
Body dismorphia is real.
Feeling you are in the wrong body is real.
No one is forcing the book onto anyone. If girls identify with what's between the pages then l reckon it won't be a shock to parents.
Having something , anything! That touch on young trans issues has to be a good thing right?
Jumping straight to having double mastectomies and constructed penises is a conversation that won't and l believe shouldn't take place for years.
Having ' the' conversation about how 'they' feel, accepting those feelings and realising that they may need medication and or cbt treatments that lasts for years is a start. It wont be easy but if it avoids self harm - l'm for it.
( I don't have a trans kid, l have a nephew who is definitely 'fluid'. As a family we are supportive. At 15, there's years for him to decide. His mental health is good but that could change. We will be there if it does. My sister and her husband have made changes to their outlook. Hope this helps someone.)