Almost 70 percent of married women in Japan believe same-sex marriage should be legalized, a government survey showed Friday.

Of those in their 30s or younger, roughly 90 percent supported the legalization of same-sex marriage, the survey last year by the National Institute of Population and Social Security Research said.

The survey, which covered about 6,000 married women, has been conducted every five years since 1993 to collect data on domestic households, such as distribution of chores. Questions on same-sex couples were added for the first time last year.

On surnames, the ratio of those who said it was acceptable to have a different last name than their husband's rose 9 points from five years ago to 50.5 percent, eclipsing half of all respondents for the first time.

Married couples are required by law to use the same surname. Although the law does not state which partner must give up the surname upon marriage, it is customary for the wife to take her husband's name.

"Attitudes toward family are changing," said an official in charge at the institute, which is affiliated with the Health, Labor and Welfare Ministry.

The survey reflects the responses of 6,142 married women who were sent questionnaires by the institute and excludes those who are divorced or widowed.