1. Children lack context and developmental maturity needed to make an informed decision on any such life-altering decisions.
2. Transsexuality is a mental disorder that's being normalized through media exposure, and as seen with split personality disorder, this can lead to increased false positives, which children are not prepared to detect.
3. There is a marked increase in suicide rates among people afflicted with genuine gender dysphoria. Whether a false positive or a actual case of it, if it is possible to prevent the onset of the disorder, then a guardian of a child (who has poor judgment skills) should be duty-bound to defend that child's life by suppressing it until they're older and better equipped to deal with it.
4. A bad guardian can lead to bad future outcomes down the road. Someone encouraging either a mental disorder or a false-positive of one is a bad guardian.
5. Kids are barely sexual/gendered creatures to begin with. Most of their personality traits are still in flux. There is no reason to inject potentially harmful sexual/gendered beliefs into their minds as they're growing and processing the world, especially before puberty, when that stuff emerges naturally.
Also ur a faget and anime.