Lawmakers from the ruling Democratic Party of Korea (DPK) have introduced a bill that would allow married couples to decide whether their child takes the mother's surname at the time of birth registration, rather than only at the time of marriage registration.

The amendment to Article 781 of the Civil Act, proposed last week by Rep. Park Ju-min and 14 other DPK legislators, would expand the window during which parents may agree to give a child the mother's surname.

Under current law, children in principle take their father's surname and family origin. Parents may use the mother's surname for their children only if they make that agreement when registering their marriage — an option created by the 2005 Civil Act reform that abolished the male-centered family head (hoju) system. As a result, couples are asked to decide on the surname of a future child — often long before they know whether or when they will have any children.

The bill would retain the father-surname principle but permit parents to make the agreement either when registering their marriage or when reporting the child's birth.

"There can be a considerable interval between the registration of a marriage and the birth of a child. At the time of marriage registration, it may not yet be known whether the couple will have a child or when the child will be born," the lawmakers said in the proposal.

They added that the bill is intended to ensure parents have a substantive choice while more fully realizing the constitutional principle of gender equality in marriage and family life.

The proposal stops short, however, of abolishing the default rule that children follow their father's surname — an idea supported by liberal groups.

That idea was previously taken up during the left-wing Moon Jae-in administration. In 2021, the government's Fourth Basic Plan for Healthy Families said it would pursue a revision replacing the father-surname principle with a system based on parental agreement.

The reform did not result in a legislative revision. After the change of government, the Ministry of Justice reversed course, telling the Constitutional Court in 2022 that the existing rule did not infringe on constitutional rights. It cited concerns about siblings having different surnames and the traditional significance of surnames within families. The ministry also said further discussion and broader social consensus were needed before pursuing legislative reform.

The bill now awaits review in the National Assembly's Legislation and Judiciary Committee, where civil rights and family law revisions are typically considered before facing broader social debate over the surname system.