Japanese Prime Minister Fumio Kishida on Thursday struck a cautious tone about legally recognizing same-sex marriage in line with other Group of Seven countries that have already adopted the practice.

"We need to be extremely careful in considering the matter as it could affect the structure of family life in Japan," Kishida said at a parliamentary session, although several lawsuits have been filed across the nation by same-sex couples.

Japanese Prime Minister Fumio Kishida speaks at a House of Councillors plenary session in Tokyo on Jan. 26, 2023. (Kyodo) ==Kyodo

Japan has not acknowledged same-sex marriage, as many members of the conservative Liberal Democratic Party, led by Kishida, have opposed the concept, emphasizing the country's traditional values, such as the role of women in giving birth and raising children.

Late last year, the issue drew fresh attention as LDP lawmaker Mio Sugita, the then parliamentary vice minister for internal affairs and communications, was forced to retract past remarks against sexual minority couples.

Sugita, who was effectively sacked by Kishida in December, came under fire in 2018 for saying in a magazine article that the government should not support sexual minority couples because they cannot bear offspring and thus are not "productive."

Meanwhile, left-leaning opposition parties have endorsed reforms around family issues, including recognizing same-sex weddings and allowing married couples to take separate surnames -- another controversial topic in Japan in terms of gender equality.

Asked by an opposition lawmaker at the plenary session of the upper house on Thursday about a legal revision to enable married couples to use different surnames, Kishida avoided answering the question directly.

"As there are a variety of views among the public, it is necessary to gain wider understanding through sufficient discussion," the premier said.

While Japan's Civil Code requires a married couple to share a surname, the vast majority of couples who register their marriage in the country choose the husband's family name.

Japanese conservatives, who typically cherish traditional values, are opposed to separate surnames, arguing that the move may have an impact on family unity as well as on children.

But the U.N. Committee on the Elimination of Discrimination against Women has recommended that Japan introduce reform to the system.

Related coverage:

Plaintiffs appeal Tokyo court ruling on same-sex marriage

Tokyo gov't begins recognizing same-sex partnerships

Japan court rejects long-stay visa for U.S. man in same-sex marriage