I think it would be very humiliating for a boy to be hypogonadic, or even castrated, and have to shower or take physical education classes with his peers who would be far more developed than he is. He would, no doubt, be an object of ridicule and be miserable.
Personally, I recall being the most under-developed boy in the showers, being made fun of, not shaving until I was 17, little to no muscle mass, and I never had much HRT ... although I am 99% sure I had SOME during my teen years. No one needs THAT many tetanus boosters when you're not cut open!
One advantage is that I have arms that can reach damn nigh anything, though.
That, and the medical community seems to have this issue with "manhood." Preserve it at all costs. Doctors are even loathe to admit that things can go wrong "down there" at any age. HRT would restore and insure little Billy's maleness, thus keeping him in the "norm". Therefore, little Billy now gets HRT and probably prostheses as well, whether he wants them or not.
Of course, this now brings us back to the issue of
" post that Jesus A. mentioned. When is the boy old enough, or should the parents wait, for him to understand whether to undergo puberty/implants or not?
After all, he's a boy ... he should look and act like one, right?! (tongue firmly planted in cheek)