There's not much evidence for anything about trans people since it's a very new phenomenon in the social consciousness, but you can be ruining someone's life by appealing to that scientific ignorance + your anecdata mixed in.
Just trust the latest collective consensus of psychologists and doctors, and encourage others to do the same. They're paid to know about this stuff and to onboard the enormous risk you are with your prescriptions in this thread.
That's interesting, I have the complete opposite position. Doctors and psychologists can give a informed guess at best. What you hear will vary wildly by the person you select.
I don't think it is practical to put the risk or responsibility on them. Ultimately it comes down to the patients and their parents who have to decide what they think is right and live with the consequences, good or bad.
Trans people have always existed. The way they are accepted or not accepted into societies fluctuates.
There is one obvious harm: puberty.
If your kid is transitioning male-to-female, then if she doesn't get treatment, she will grow facial and body hair and have her voice deepen. If they are female-to-male, they will grow breasts. (This is not an exhaustive list.) Some trans people are fine with being obviously non-gender-conforming, but a lot of them aren't. I don't have a price chart in front of me, but I'm pretty sure that electrolysis and breast reductions are more expensive than a few years of hormones, and while voice training can help with their voice, there's only so much it can do.