The Supreme Court of Japan has declared that it is against the constitution to mandate citizens to undergo sterilization before they are permitted to change their officially recognized gender.

The law from 2004 stipulated that individuals could only change their legal gender if they were unable to reproduce.

The Wednesday ruling occurred in response to a petition filed by a transgender woman challenging the law. 

Human Rights Watch (HRW) had previously criticized the law as "abusive and outdated.” They celebrated the Wednesday ruling, hailing it as a significant triumph for transgender rights in Japan.

Kanae Doi, Japan Director at HRW, conveyed that the judgment affirms the rights to health, privacy, and bodily autonomy of transgender individuals in Japan. She added that it comes after years of advocacy and legal efforts aimed at eliminating this abusive requirement.

This ruling represents a reversal of a previous 2019 verdict by the court, which had deemed the same law to be constitutional at that time.

Japan is one of 18 countries that enforce the requirement of sterilization surgery, a mandate that is also opposed by the World Health Organization. Additionally, it is the only nation in the Group of Seven (G7) that does not legally recognize same-sex unions.

The woman's lawyer had presented the argument that her reproductive capability had already been reduced due to years of hormone therapy, and that the surgery involved physical suffering and the risk of postoperative complications. Her request had been rejected by both the family and the high court before she appealed to the Supreme Court.

Some groups opposing changes to the law had argued that if individuals were permitted to change their legally registered gender without undergoing surgery, it might lead to concerns about the safety of women. They also contended that it could create legal uncertainties.

Recent opinion polls have indicated an increasing level of support for LGBTQ-friendly laws in Japan, although there remains opposition from conservative segments of society and some politicians.

Earlier this month, a local family court ruled in favor of a transgender man named Gen Suzuki, who had requested to legally change his gender without the requirement of undergoing surgery.

The family court judge, Takehiro Sekiguchi, stated that the current law was in violation of Article 13 of the Constitution, which mandates that all individuals should be respected as individuals.