http://www.straitstimes.com/BreakingNews/Asia/Story/STIStory_807301.html
Decreasing wages of young men accelerates lower marriage rate and lower fertility rate.
And, more and more women get out into the world. Then, at a glance, families whose fathers do housework can increase. But, this phenomenon is still a rare case, because most of the Japanese people at the age of 40s or 50s assume that men should get out into the world and feed their wives. They wouldn't accept the opposite case. One of the reasons is that they didn't have difficulty in job-hunting.
So,a kind of family consists of a working wife and a housekeeping husband hasn't yet prevailed widely.
This dilemma seems to be a cause of lower fertility rate.
