Again - a narrative to suit, with no evidence to substantiate...
the reality is that parents provide balance as children grow up... the child who believes they are a dinosaur aged three is humoured as age appropriate imaginative play - but still has to eat dinner / have a bath and go to bed
as they get older parents give more credence to the emerging child / teenager / adult - but they still provide balance from their wider experience of life
a child going to university is for the first time predominantly outside that parental balance, so it becomes an opportunity for other voices to speak louder and to influence more strongly - and sometimes those other voices have an agenda and speak a world of lies and deceit in a way that sounds convincing...
It is why we have seen an increase in teenage incidences of belief in gender ideology, because we have moved into a world where those outside voices have a way into the teenage child's bedroom past the parental balance through online and social media.
It is why we see such a vast correlation between 'trans' and autism / sexual abuse / child abuse / disturbed childhoods / etc. - because these outside voices need something to feed on, uncertainties to nurture, lack of confidence to bolster, hurts and pain to exploit... and those children are vulnerable from an early day - but become more accessible through online means, and even more accessible once out in the open and away from family life.
If your narrative were correct and the TRA statements about 'you are born trans' / 'it is who you are' / etc. had any validity, then the stat profile would be vastly different - then you would have children from every type of background in equal proportions - NT and Autistic in balance / abused and not abused equal / those with and without mental health histories equally coming out as 'trans'...
but we don't so your narrative is wrong.
We have seen an explosion in numbers because we live in a world increasingly vulnerable to mental health issues, with technology enabling and accelerating it, where any voice can access a young person and it is difficult to balance or fight those voices... not because historically there have been huge numbers of 'trans' people who have been afraid to reveal themselves - the reality is that you can not be 'trans' because no-one can change sex, so all of this movement now is a mental health issue exploited by those with very questionable aims...
and in most cases that is not the parent... (though parents who enable and encourage 'trans' is a whole different discussion as is any other form of child abuse).