TOKYO, Jan. 29 (Xinhua) -- Some Japanese female lawmakers urged health minister Hakuo Yanagisawa to resign on Monday for calling women "birth-giving machines" in an earlier speech.

Japanese Health Minister Hakuo Yanagisawa listens to a legislator at parliament in Tokyo, Jan. 29, 2007. (Xinhua/AFP Photo) Photo Gallery>>>

    The protest letter to Yanagisawa, signed by 16 female lawmakers, said that his remarks treaded on women's human rights and were totally unacceptable. The letter also urged the minister to resign over the issue.

    Yanagisawa said on Saturday to a local assembly that "the number of women aged between 15 and 50 is fixed. Because the number of birth-giving machines and devices is fixed, all we can ask for is for them to do their best per head," according to Kyodo News.

    The remarks immediately drew criticism from opposition parties and the ruling bloc. Prime Minister Shinzo Abe told the Diet that he has strictly warned the minister about the inappropriate comparison on Monday morning.

    Yanagisawa apologized on Monday for making the remarks, saying "I used such an expression to make it easier to explain about population projections. It was really inappropriate."