Children have become more of a burden than a benefit in many ways. We once had much use for our children. When people were more independent and everyone pretty much had a small business, children were seen as the life blood of that business. Now, we are pretty much expected to fill a role at some large corporation -- which Japan is the greatest example of. Also, the family centered culture has changed to a work cente…
It isn't just the choices. Young people are having less sex. Japan has noticed this. Declining sales of contraceptives but declines in both STDs and pregnancies, especially amongst the young. Incidents of the "oops we are pregnant" scenario have declined all over the western world. Western culture has for decades complained that young people have too liberal a view of sex. Remember those abstinence pushes in the 80s…
That's my take anyway.