will continue to talk about his remark until the Upper House election" in July, said Ikuo Kabashima, a University of Tokyo professor who studies voting behavior. "The negative image will probably continue to follow (the LDP) in every election that takes place."

Yanagisawa made the remark during a Jan. 27 speech on the declining birthrate and the strained social welfare and pension system.

"The number of women aged between 15 and 50 is fixed," Yanagisawa said during the speech in Matsue, Shimane Prefecture. "Because the number of child-bearing machines and devices is fixed, all we can ask for is for them to do their best per head."

The remark outraged the opposition parties, which demanded Yanagisawa's immediate dismissal. The Democratic Party of Japan, the largest opposition force, the Social Democratic Party and Kokumin Shinto (People's New Party) plan to boycott all Diet committee meetings until Yanagisawa steps down.