Under Japan’s Civil Code (Articles 772-779), parentage is determined by:
(a) The birth mother, who is automatically the legal mother (Article 772).
(b) The biological father, presumed to be the legal father if married to the mother at conception or birth (Article 772), or if he acknowledges paternity (Article 779). For unmarried couples, paternity requires voluntary acknowledgment; court establishment is rare.
In informal sperm donation (e.g., at-home AI or natural insemination), the donor may be recognized as the legal father only if he acknowledges the child (Article 779). Without acknowledgment, paternity is not legally established, though courts could intervene if intent or involvement is proven.
Assisted Reproduction:
Japan regulates ART through guidelines from the Japan Society of Obstetrics and Gynecology (JSOG), not statutory law. Sperm donation is permitted only for married heterosexual couples in licensed facilities, with strict donor anonymity and no payment allowed.
Informal sperm donation is not explicitly illegal but is discouraged and unregulated. Donors lack legal protections, and cultural stigma limits its practice. JSOG guidelines do not apply to informal settings.
Single women and same-sex couples are barred from accessing regulated ART, leading some to seek informal donation.
Sperm Donor Agreements:
In regulated ART, donors are anonymous and have no parental rights or obligations per JSOG guidelines. Informal sperm donation agreements are not legally binding under Japanese law.
For natural insemination (NI) or informal AI, a donor could be deemed the legal father if he acknowledges paternity (Article 779). Private contracts may be considered as evidence of intent but lack enforceability without acknowledgment.
Surrogacy:
Surrogacy is not regulated by law in Japan and is banned by JSOG guidelines. The birth mother is the legal mother (Article 772), and intending parents must adopt the child post-birth, a process courts rarely approve.
Commercial surrogacy is not practiced, and international surrogacy arrangements face significant legal hurdles for recognition.
Parentage Agreements:
In regulated ART, parentage is formalized through marriage and birth registration. Informal agreements (e.g., co-parenting or donor contracts) lack legal enforceability and carry risks.
Paternity depends on voluntary acknowledgment (Article 779); courts rarely establish it without donor consent, but disputes could alter this.