Part two

As I just posted - if everyone is in agreement hormone blockers will be administered prior to the onset of puberty.  Widely used in cases of precocious puberty the effects are completely reversible - just stop taking them and puberty restarts on its own.  This gives the child more time (years actually) to decide how they want to proceed.  Cross sex hormones (estrogen or testosterone as the case may be) won't be administered until sometime in their teen years and, as a matter of law, surgery can't be performed before age 18.