While rights group welcomed the landmark verdict, a decision by the judges to ask a lower court to deliberate on a separate clause, requiring that the genital organs of people who want to change their gender resemble those of the opposite gender, was met with disappointment.

“This decision was very unexpected and I’m very surprised,” the plaintiff, identified only as a transgender woman under the age of 50, said in a statement read out by her lawyers.

Deputy Chief Cabinet Secretary Hiroshi Moriya told a regular press conference on Wednesday that the government will “examine the decision closely and respond appropriately”.

Those requirements are: being at least 18 years old; not being married; not having underage children; having genital organs that resemble those of the opposite gender; and having no reproductive glands or ones that have permanently lost their function.

The plaintiff’s lawyers — Kazuyuki Minami and Masafumi Yoshida — argued that the last two requirements violated their client’s constitutional right to pursue happiness and live without discrimination, and posed significant physical pain and financial burden to transgender people.

While many countries have moved to repeal laws requiring surgery to legally change gender, transgender rights remain a sensitive topic in socially conservative Japan.

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