What the law allows
Full record
Japan’s psychiatry society still permits puberty blockers and, in defined cases, opposite-sex hormones before 18.
The official 性別不合に関する診断と治療のガイドライン（第5版） (corrected 19 November 2025; PDF) keeps 二次性徴抑制療法 (puberty blockers (GnRH agonists) from Tanner 2) and 18歳未満のホルモン療法. Hormones are in principle from 18, but may start from 15 after a year of team observation if specially needed, and under 15 after about two years of pubertal suppression if the team judges the change necessary. Two written opinions and a report to JSPN are required. The fifth edition cites Cass and adds cautions; it does not withdraw the treatments.