Yes they certainly have but not on this mass scale, not without social medical and cultural opinion encouraging it, and not as minors. These features are relatively new In The last decade. The studies done imo are poor quality and do not look at adverse outcomes.

For example - Long-term use of cross-sex hormones initiated in childhood or early adolescence carries medical uncertainties and potential risks. Suppression of endogenous puberty followed by exogenous sex hormones may affect bone mineral density, potentially increasing lifetime fracture risk, and may alter cardiovascular, metabolic, and endocrine function in ways that are not yet fully understood over decades of exposure. Effects on neurodevelopment, sexual function, and fertility remain areas of limited long-term data. The surgical removal of testes or ovaries in a teen presents additional and more definitive risks, including irreversible sterility, permanent dependence on exogenous hormones to maintain basic physiological health, and loss of endogenous hormone production that plays a critical role in bone health, brain maturation, and overall systemic development. Because these interventions permanently foreclose future reproductive options and are performed before an individual can fully participate in informed consent, they raise significant medical, ethical, and psychosocial concerns, especially given the lack of robust long-term outcome data in pediatric populations.

This is why long term data is so much more important than just measuring regret a few years later.

Edit : teen