There isn’t much data, because not many people (child or adult) medically transition. But if you want to follow the data we need to do what we were doing before all this moral panic about trans kids kicked in: cautiously allow kids to transition(1), and collect data about outcomes. It’s disingenuous to complain about bad data in one breath, while blocking any path that would create new data.

(1) by transition i mean socially transition and go on puberty blockers if they want them.