The rapid-onset gender dysphoria controversy centers around the concept of rapid-onset gender dysphoria (ROGD), proposed to be a subtype of gender dysphoria caused by peer influence and social contagion. It has never been recognized by any major professional association as a valid mental health diagnosis, and its use has been discouraged by the American Psychological Association, the American Psychiatric Association, the World Professional Association for Transgender Health, and other medical organizations due to a lack of reputable scientific evidence for the concept.Apparently a lot of people believe that teenaged transgenderism is all a big fad, and this controversy has been invented to rebut that.
If the rapid onset never happened, then I would expect some scientific papers measuring how long it takes to acquire gender dysphoria. However, the references have none of that. Instead, they harass those who write about the rapid onset, and complain that discussion of rapid onset dysphoria leads policymakers to rush to castrating teenaged boys, and other irreversiable damage.
This whole subject has been overly politicized, with the major psychological associations on the side of mutilating children. There no good science to back up what they say and do.