Ideally they wouldn't need to force anything. These conversations could just happen openly enough and early enough that those decisions could be made in time for them not to be an issue.

But given that's not the world we live in, generally what's been done previously is monitoring by a doctor for things like serum testosterone levels like they already do for HRT regimens. That would unfortunately open the door for situations where a kid might not qualify depending on how early they might be in their transition but unfortunately as long as our mere existence as trans people is questioned and kids are told to wait and suffer through puberty for bodies that don't align with their identity "just in case" they "aren't actually trans" because "what if they regret it later?" then there's not a whole lot we can really do about that aspect.