Japan: Transgender Man Sues for Paternity of Child Born via Own Egg

On September 18, 2026, a Tokyo family filed a formal domestic petition before the Tokyo Family Court seeking legal recognition of paternity between a transgender man and the child he is raising with his wife. The legal action directly challenges municipal administrative practices that continue to exclude gender-affirming reproductive technologies from established civil registry procedures.

Prior to undergoing legal gender transition procedures, the man cryopreserved his own eggs. One of the preserved eggs was subsequently fertilized using donor sperm, and his female partner successfully gave birth to the child in November 2024. After legally completing his gender marker change to male, the couple married in February 2025. Following their marriage, he submitted an official notification seeking legal acknowledgment of the child as his own, but local municipal authorities refused to accept the submission, arguing that a legally recognized biological father-child relationship did not exist because he was not the sperm provider.

The legal counsel for the family vigorously disputed the municipal government's statutory interpretation before the court. Attorneys argued that an undeniable biological link exists between the man and the child, emphasizing that provisions governing paternity acknowledgment in the Japanese Civil Code do not explicitly mandate that a legal father must provide sperm. Furthermore, the lawyers cited a landmark 2024 Supreme Court ruling involving a transgender woman whose frozen sperm conceived a child, in which the court held that legal paternity acknowledgment can proceed regardless of the parent's legal gender, asserting that identical protections must apply when a transgender man supplies the egg.

From an institutional perspective, the ongoing litigation highlights critical legislative gaps at the intersection of Japanese family law and modern assisted reproductive technology. Without formal legal parent-child recognition, the family faces acute administrative vulnerabilities regarding parental authority, inheritance succession, and emergency medical proxy decisions for the child. While the Tokyo Family Court deliberates on the petition, the forthcoming judicial ruling is poised to set a historic precedent for the statutory recognition of diverse family structures across Japan.

Asian Editorial Department: Kim Min-jun

Source: Compiled from Japan Gay Guide reports

References

Courts in Japan - Official Judicial Portal

Ministry of Justice of Japan - Civil Affairs Bureau

Japan Federation of Bar Associations (JFBA)