The debate on consanguineous marriage is heating up, as the government appears to be moving toward easing laws related to intrafamily marriage.

Currently, South Korea prohibits marriage between blood relatives within eight degrees of relations ("chon" in Korean), according to the Civil Act, Article 809 and Article 815. That means that Koreans may not marry third cousins -- their grandparents' cousins' grandchildren -- or closer relatives.

Article 809, Section 1 states that “a marriage may not be allowed between blood relatives within the eighth degree of relationship.” Article 815, Section 2 declares that “a marriage is null and void if Article 809, Section 1 is violated.”

The Ministry of Justice says it is now looking into reducing the scope of the country's ban on consanguineous marriage following a constitutional ruling that an annulment of marriage within eight degrees of blood relations does not conform to the Constitution.

“We will make an amendment considering the change in time and national sentiment based on thorough investigation and discussion processed by the Family Litigation Act Revision Committee,” the Justice Ministry said.

The move, however, sparked instant opposition from traditionalists, particularly those who uphold Korean Confucian beliefs. Korean Confucian institutions and organizations issued a statement Tuesday that such consideration was “an act of family destruction.” It also demanded that the Justice Ministry stop such research.

The Ministry of Justice's decision stems from a Constitutional Court ruling in 2022. While the law prohibiting marriage between blood relatives within eight degrees of blood relations was deemed constitutional, the annulment of consanguineous marriage after the fact was found to be unconstitutional.

The Constitutional Court issued the decision after a man sought to nullify his marriage due to being within the sixth degree of blood relations -- second cousins -- with his wife. A lower Korean court found their marriage, registered on May 4, 2016, to be between blood relatives within the eighth degree and confirmed the nullification. The wife appealed the decision to the Daegu Family Court and requested a constitutional review of the law that served as grounds for the nullification of their marriage.

The Constitutional Court explained that if marriage is rendered void uniformly and retroactively after giving birth to a child or circumstances exist where there seem to be expectations of trust and cooperation within the family, this may lead to results at odds with the original legislative purpose of maintaining the functions of the family institution.

The court recommended revising the law by the end of this year but advised that it should remain effective until amended, the ministry said, adding that is why it was researching the impact of reducing the scope of the ban on marriage between blood relatives.

Hyun So-hye, a professor at Sungkyunkwan University Law School who is conducting the study, said the move to revise the law appears to have emerged as the number of people who maintain family ties with relatives beyond the fifth degree of blood relations -- first cousins once removed -- has decreased significantly compared to the past.

Other reasons included genetic perspectives and international examples.

From a genetic perspective, in the case of marriage between blood relatives who are fifth to eighth degrees of blood relations (first cousins once removed to second cousins once removed), the likelihood that the child will develop a genetic disease is almost the same as in the case of children from non-consanguineous marriages. In the case of consanguineous marriages within the fourth degree of consanguinity (first cousins), the incidence of genetic diseases for a child is approximately 2 percent higher than in non-consanguineous marriages, but there is no causal relationship at the fifth degree or beyond, according to the research.

Considering global standards, South Korea is especially restrictive. For instance, Germany, Switzerland and Austria allow marriages between collateral blood relatives of fourth degree relations (cousins) or beyond. Many states of the US, the United Kingdom, France, Italy and Japan allow marriages between collateral blood relatives of fifth degree relations (second cousins) or beyond, according to the study.