A court on Wednesday found constitutional a legal provision that allows only men and not women to file a lawsuit denying the legal fatherhood of a child, dismissing a claim filed against the state by a family for damages related to the accuracy of their legal paternity.

The ¥2.2 million damages suit was filed with the Kobe District Court by a woman in her 60s living in Kobe, as well as the woman’s two grandchildren and her daughter who is in her 30s.

The plaintiffs argued that the Civil Code provision allowing only men to deny legal fatherhood is discriminatory and unconstitutional. They plan to appeal to a higher court.

Presiding Judge Kazuhiko Tomita, however, said the legal provision is reasonable as it represents a compromise between the need to match biological and legal fathers, and ensuring stable paternal relations by determining them promptly.

The lawsuit was the first court challenge over constitutionality of the legal provision, according to the plaintiffs’ lawyers.

According to the suit, the woman lived apart from her husband because of his violence and had a baby girl with a different man in the 1980s.

She then filed to register the birth of the daughter with the second man only for the birth report to be rejected, due to another Civil Code provision specifying that children carried by married women are “presumed” to have been fathered by their husbands.

The Kobe woman considered asking the former husband to file a lawsuit to reject his legal paternity of the daughter, but decided against it as she wanted to stay away from him.

As a result, the daughter and her two children were placed outside the official family registration system until last year.

The plaintiffs claimed they suffered mental anguish and other disadvantages. For example, the daughter was not able to get married legally and her children did not receive notifications for enrollment in school or medical checkups.

They argued such a situation could have been avoided if wives and children were also allowed to file lawsuits concerning legitimacy under the Civil Code.

In the ruling, the judge highlighted the need to develop legal institutions to safeguard privacy in judicial proceedings and protect women from violence, adding that wives could otherwise find it difficult to file lawsuits for paternity denial even if they are granted the right to do so.

According to the Justice Ministry, 715 residents across the country were unregistered as of Oct. 10. Their birth notifications had not been submitted to local governments due to their parents’ circumstances and other reasons.