[Japan] Why Adoption Means Same-Sex Couples Can Never Marry
I'm Minaduchi, a gay man from Japan.
Japan remains the only G7 nation without marriage equality.
Same-sex couples who want legal family ties are told to "just adopt each other." But this turns equal partners into "parent" and "child." And Article 736 permanently bars them from ever becoming spouses.
🎭 30 Years Together, Rewritten as "Parent" and "Child"
At the city hall counter, the form has two boxes: "Adoptive Parent" and "Adopted Child."
They've been together for 30 years.
They split the rent.
They nursed each other through illness.
They were equals.
But the form says one must be the "parent" and the other the "child."
Because adoption requires the adoptive parent to be older, the roles are structurally fixed, even if the age gap is just a few months.
At the next counter, a young couple files a marriage certificate.
One sheet of paper.
They become legal spouses.
Same city hall. Completely different exits.
[NOTE] The above is a fact-based story to illustrate the problem. From here, I'll explain the actual situation.
📋 What Adoption Provides and What It Cannot
Adult adoption creates a parent-child relationship, not a spousal one, and the protections it provides fall far short of marriage.
Adoption does grant some legal effects: inheritance rights, shared family registry, mutual support obligations, and avoidance of the 20% inheritance tax surcharge.
Compared to the status of legal strangers, these are meaningful gains. But these benefits are limited to inheritance and support. They operate under a fundamentally different logic than the spousal rights system, which is built on the premise of equality between partners.
The rights that come automatically with marriage remain out of reach:
No property division: Dissolution is "severance," not "divorce," with no legal basis to split shared assets (Article 768 applies only to marriage)
No spousal tax benefits: The spousal income deduction (up to ¥710,000/year) and inheritance tax exemption (up to ¥160 million) do not apply
No survivor's pension: The right to receive a survivor's pension is limited to spouses
Partnership certificates, now covering over 530 municipalities (92.5% of Japan's population), carry no legal force. The government expanded 33 laws in 2025 to potentially include same-sex partners, but marriage, tax, inheritance, and pension systems remain excluded. Approximately 120 social security-related laws are not covered by this expansion.
🔒 The Irreversible Trap of Article 736
Under Article 736 of Japan's Civil Code, marriage between a former adoptive parent and child is permanently banned, even after the adoption is dissolved. This means adoption cannot serve as a stopgap until marriage equality arrives.
Once a couple enters an adoptive relationship, they face a dead end:
Dissolve the adoption → Article 736 permanently bars them from marrying
Keep the adoption → They remain "parent and child"
Either way, they can never become equal spouses. This is information that every couple considering adoption deserves to have before making an irreversible choice.
Contested dissolution requires court proceedings under Article 814, with limited grounds such as "malicious desertion" or "serious reasons making continuation unbearable," a higher bar than divorce.
⚖️ Where the World and Japan's Courts Stand
Globally, 38 to 40 countries have legalized same-sex marriage. Taiwan became Asia's first in 2019, and public support for marriage rights rose from 37.4% to 69.9% by 2025 (NDC survey). Support for adoption rights for same-sex couples also reached 76.9% (Taipei Times, 2024).
Thailand's marriage equality law took effect in January 2025, making it Asia's second country to legalize same-sex marriage. A 2024 RAND review found no credible evidence that legalization harmed heterosexual marriage rates.
In Japan, five of six high courts have ruled the exclusion of same-sex couples from marriage unconstitutional. The Osaka High Court stated that a separate system would constitute "a new form of discrimination," and the Fukuoka High Court found that alternative systems are "insufficient." A Supreme Court ruling could come as early as 2026, but for couples who have already adopted, the barrier of Article 736 remains.
📝 Summary: The System Forces an Impossible Choice
Adult adoption was not designed to protect partnerships. Yet it is the only path to "legal family" for same-sex couples in Japan. When they take it, their equal partnership is rewritten as a hierarchy, their spousal protections vanish, and Article 736 closes off their right to ever marry.
This article does not intend to deny the decisions of those who chose adoption after careful consideration. The choice to protect a relationship with a loved one within limited options deserves sincere respect. But the problem is the system that forces such a choice.
Without an exception to Article 736, the very couples who need marriage equality the most will be left behind on the day it arrives. Whether through a transitional provision in future legislation or a judicial exception, a path must be created. Knowing about this issue and sharing it is the first step.
References:
Civil Code of Japan, Articles 736, 768, and 814
RAND Corporation, "The Effects of Same-Sex Marriage Laws on Different-Sex Marriage and Fertility" (2024)
Osaka High Court ruling on same-sex marriage (2024)
Fukuoka High Court ruling on same-sex marriage (2024)
Taiwan NDC survey on same-sex marriage (2025)
National Diet Library, summary of partnership certificate systems in Japan
This article includes a fact-based story to help illustrate the problem. The story portions have been anonymized, reconstructed, and adjusted to protect privacy. All non-story content is based on publicly available information.
