It's pretty simple stuff really.

If you're going to argue that until 18 all kids are incapable of knowing they are trans. Then equally they must be incapable of knowing they are cis.

Therefore we should, if that's your best argument, put all kids on blockers until 18. https://twitter.com/AmazonEve/status/1341533993166987264

If on the other hand you are to suggest that cis children are capable of knowing they are cis and therefore progressing through the puberty they want to have unobstructed. Then you must either accept the same for trans people and allow them a right to bodily autonomy too.

There is one get out clause here but its a catch 22.

See, you could make the argument that cis kids can trans kids can't if you suggest that there's something unique about trans kids that makes them unable to understand and consent. But...

Any kid you make that argument about is essentially confirmed to be trans by way of making the argument. If you say only trans kids can't understand and consent and also your kid can't understand and consent, it follows they must be trans. Since cis kids can.

Is a paradox innit.