Cousin marriage ban poised to lose effect

Marriages between third cousins or closer relatives are prohibited in South Korea, with the ban enforced by nullifying the effects of such unions when they are discovered.

However, the ban on consanguineous marriages within the eighth degree of kinship looks set to lose its effectiveness, as a legal article governing the annulment of such unions will expire at the end of this year, with no substitute measures drafted or prepared to date.

Of the two Civil Act articles on consanguineous marriages, one – Article 809 – was ruled “incompatible with the Constitution” in a 2022 Constitutional Court decision. This granted lawmakers until the end of 2024 to enact a substitute article, while the problematic law remains intact.

The top court upheld the constitutionality of the ban itself, but took issue with the act mandating retroactive annulment for rule-breaking unions, noting that such measures could disrupt already-formed families, especially given South Korea’s lack of a system to clearly verify eighth-degree kinship in advance.

The court decision came after a man requested to annul his marriage with his wife, who was also his second cousin. While a lower court upheld the annulment, the wife appealed the ruling to the Daegu Family Court and filed the petition with the top court for a constitutional review of the law.

With no progress on amending the Civil Act over the past two years, Koreans who have married their third cousin -- their grandparents' cousins' grandchildren -- or closer relatives, whether intentionally or not, will no longer be able to annul such marriages, nor will these marriages be subject to annulment starting from next year.

"Failure to amend a provision deemed unconstitutional constitutes negligence on the part of the National Assembly and infringes upon citizens' basic rights," said Cha Jin-ah, a professor at Korea University School of Law.

As of Wednesday, the Ministry of Justice has no proposal ready to submit to the National Assembly.

"No specific direction for the amendment has been decided. It is still under review," the ministry said.

In February, the ministry faced strong public backlash after local media reported it was considering a proposal to narrow the scope of the ban from third cousins to cousins, or from eight degrees to four degrees of kinship.