This is an interesting article in a US publication about trans kids and rapid onset gender dysphoria.
After considering many aspects of the issue and anecdotal reports and data, the writer comes to the the conclusion that the distilled problem is that there is no way of determining which children are truly trans and which are not.
If we are to progress then sooner or later these mainstream writers are going to have to have the courage to say that there is no such thing as a transgender child.
http://nymag.com/intelligencer/2019/11/andrew-sullivan-hard-questions-gender-transitions-for-young.html