i've read a lot oabout this in bits and pieces (mainly new scientist a while ago)
I used to think it was a really good idea, but now i'm not so sure, i've been doing a lot of reading on childhood GID and apparently only about 10-20% of the children who show signs of GID go on to develop GID in adulthood. In some cases they just grow up gay but identifying with their biological gender, in some cases it's just a phase (appologies for the cleche).
This treatment is a bit risky. There are no immediately apparent health risks, but new and a bit of an unknown. Though puberty seems to start normally if they discontinue it there are quite a few ill effects that seem plausable: future fertility problems, psychological development, or cancers in reproductive organs (including breasts). I'd be reluctant to privide it to any except the most severe cases.
However by providing it to only severely destressed cases you risk driving moderate cases to destructive behavious (like self-harm) to get what they want at the time, even if it's not in their best interest long-term. Adolecents are strange beasts... quite hard to treat. I'm only in my 20s but there are already a few things that i want to go back and give my adolecent self a good slap for.