The very first patients to medically transition were AGPs.
Those we think of as the stereotypical transsexuals, documented from the 60s onwards, who were diagnosed with gender dysphoria in early childhood were almost always boys, girls were slightly older. The causes are evident from the papers - a disruption in early childhood development in the crucial phases of personality development.
Stage 2, age 1.5 to 3 is called autonomy vs doubt or shame
Stage 3 age 3 to 5 is called initiative vs guilt
These names hint at what happens when these stages are not resolved successfully.
Children discover their own will and seek to assert it. Preferences develop. Adverse childhood experiences disrupt this normal process in some children leading to personality disorders and/or other mental health issues. And for a tiny number (6 in 100,000), the result is gender dysphoria.
ACEs include abuse, neglect, trauma, sexual exploitation, violence, bereavement etc
Puberty is what resolves the mind and body conflict in those who go on to desist. Those who go through puberty and persist almost always transition early and are therefore not only known as homosexual transsexuals but also early-onset transitioners.
If you look at the autobiographies of transsexuals, who fall into that group, they detail in their own words what the ACEs are. In very many cases more than one ACE, but one of the most frequent is being punished (abused) for gender-non-conformity by parents or caregivers who equate being GNC with being gay or lesbian and who believe they can stop their child growing up to be homosexual by forcing them to conform to sex stereotypes.
(In actual fact, the parents were often not wrong to think that their children were going to be homosexual, they were just wrong in thinking that they could stop it from happening. Hence being diagnosed with gender dysphoria in early childhood is a much more reliable predictor of homosexuality than transsexualism.)
So for this cohort, puberty blockers are particularly harmful, because they prevent the very process that would help the majority of these children to reconcile mind and body. The Dutch arrogance here is staggering - there is no way to accurately predict before puberty who will desist. This is why watchful waiting was the approach decided on originally. That prevented the most iatrogenic harm, avoiding the medical transitioning of children who would desist. But because those Dutch clinicians treating the children did not understand that it was puberty itself that was the resolution mechanism, they developed their Dutch protocol, believing that pausing puberty would allow an unknown other resolution mechanism to happen. (This is why studies show 100% or near 100% of children put on blockers progress to cross-sex hormones.)
Rapid Onset Gender Dysphoria is a whole different kettle of fish, and it is here where social contagion must be looked at as an important factor. I am not convinced that this cohort experiences the same condition as early-onset transitioners (we obviously know that late-onset transitioners aka non-homosexual transitioners aka AGPs are completely separate from these two cohorts).