A court has said that a law requiring surgery to switch genders on a family registry is unconstitutional, as it made a ruling on a case involving a transgender man in central Japan, his lawyers said Thursday.

The Hamamatsu branch of the Shizuoka Family Court delivered the country's first judgment on a challenge to the rule after the man, Gen Suzuki, filed a request in 2021 seeking to change his gender without sex reassignment surgery.

The decision Wednesday by the central Japan court allows Suzuki, 48, to be listed as a man in his family registry without undergoing an operation to remove reproductive capacity.

He has undergone hormone therapy and surgically removed his breast tissue but believes a sex reassignment operation would have a serious impact on his physical and mental health.

Suzuki says he felt uncomfortable being treated as female from a young age and was diagnosed with gender dysphoria at age 40.