Japan's top court ruled on Wednesday that a legal clause requiring people to undergo sterilisation surgery if they want to legally change their gender is unconstitutional.
Several international organisations including the European Court of Human Rights, the World Professional Association for Transgender Health and UN experts had said the requirement was discriminatory and infringed upon human rights.
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. She added, however, that she was "disappointed" that a decision on the other clause had been postponed.
Some lawmakers and women's groups in Japan had said a ruling that challenges the existing law would sow confusion and undermine women's rights. The Supreme Court threw out a similar bid to scrap the sterilisation requirement in 2019.
Human Rights Watch said Wednesday's ruling meant the government now had to follow up.
"The government is under the obligation to make any laws constitutional so the government now needs to act quickly to remove the clause," said Kanae Doi, Japan director of the rights group. "It's late, but never too late.
Deputy Chief Cabinet Secretary Hiroshi Moriya told a regular press conference on Wednesday that the government will "examine the decision closely and respond appropriately".
Japanese law states that people who want to change gender must present a diagnosis of gender dysphoria and meet five requirements.
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.
"The issue that there are people who have to suffer the incongruity between one's own gender and the legal status of one's gender, as well as the problems of living in such a society, remains unsolved," Minami said following the ruling.
While many countries have moved to repeal laws requiring surgery to legally change gender, transgender rights remain a sensitive topic in socially conservative Japan.
A petition organised by seven groups that support the surgery requirements collected more than 20,000 signatures as of Tuesday.
Protect the Definition of Women, a group that supports upholding the surgery requirement, submitted a separate petition to the Supreme Court last week, saying dropping the requirement would "significantly violate women's rights and dignity".
Last month, a group of lawmakers from the ruling Liberal Democratic Party issued a statement saying any ruling that deemed the law unconstitutional would sow confusion.
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