Japan: Osaka High Court Rules Lack of Nonbinary Gender in Family Registry Unconstitutional

The Osaka High Court ruled that Japan’s family registration system violates the country’s constitution because it only allows for male and female gender markers. In a May 8 decision, the court found that the lack of an option for nonbinary individuals violates Article 14 of the Japanese Constitution, which guarantees protection against discrimination.

“Koseki” is a mandatory national registration system in Japan. It tracks the births, deaths, and marriages of citizens, and the records are maintained by municipalities. In these documents, a child’s gender is traditionally designated in strictly binary terms, such as “eldest son” or “eldest daughter”.

The litigation began in December 2024. A 50-year-old nonbinary resident of Kyoto Prefecture petitioned a family court to change their gender marker in the “koseki” system. The plaintiff sought to replace the designation “eldest daughter” with a gender-neutral term, such as “eldest child”. The Kyoto Family Court initially rejected this request.

Upon appeal, presiding judge Masahiro Oshima upheld the refusal to change the marker for the specific plaintiff. The court explained that the system must operate uniformly across the country, and changing the rules based on an individual request is currently not feasible. However, the court ruled that the national system needs to be reviewed because excluding nonbinary people violates equality guarantees. If the government adds a nonbinary option to the “koseki”, the plaintiff’s request will be reconsidered.

As reported by The Asahi Shimbun , the court deemed it appropriate “to open a path for making corrections in a form that matches an individual’s gender identity”. The Japan Times quoted the court’s statement that gender identity is “directly connected to an individual’s personal existence, making it a significant legal benefit”.

The plaintiff’s lawyer, Shun Nakaoka, emphasized in a comment to The Japan Times that prior to this decision, nonbinary gender identity was not legally recognized in Japan. According to the defense attorney, the court’s statement marks a crucial step toward the legal recognition of nonbinary people in the country.