70% of Japanese answered "it's hard to find a job which supports raising children". Japanese society is still rooted in women quitting when they have kids and being stay at home moms. Even though now 60% of couples have two earners, this hasn't changed fast enough. The economy is doing badly too, and people have less money than before.

In Japan, marriage = kids, there are few children born outside of marriage. Increasingly people are marrying later or not marrying at all, which has a direct effect on that. There are other reasons: women still end up doing way more of the housework and childrearing than men (on average) in Japan; men work longer hours and don't get to spend time with the kids they're raising; in a divorce women almost always get full custody. Mother in laws used to live with the family and help, but that is less common now. Two earner households are more common. Women are focusing on careers more.

The overall picture is similar to other countries - a rejection of the traditional marriage and kids plan in favour of spending time on other activities in ones 20s and 30s - but unique societal factors make it more prominent here.