Lisa Littmans research behind „rapid onset gender dysphoria” is a survey amongst parents recruited on three anti-trans internet sites and communities:
https://psychcentral.com/lib/there-is-no-evidence-that-rapid...
The study was based on 256 responses to an online survey of parents recruited from these three websites
That by itself means its heavily biased research on a weak sample.
„Stats for Gender” site is ran by Genspect, which is also a biased source on the subject:
Organization that supports position <x> supports position <x>.
If Genspect can be discarded as being a biased source, then so can WPATH and every other org supporting gender ideology.
Given the fraught nature of the debate, Wikipedia seems like a poor source for determining the bias of players in the debate - the most passionate debaters have plenty of time to just edit Wikipedia.
The primary issue with Genspect is poor scientific rigour applied to their publications, as I have shown above. Pretty much „if it fits our platform, we will spread it”.
Rapid-onset gender dysphoria is a well documented phenomenon.
https://www.jahonline.org/article/S1054-139X(16)30765-0/abst...
https://statsforgender.org/since-the-turn-of-the-millennium-...