as more people are educated and have broader view of the world, they concentrate more on their own life quality rather other being dedicated the whole life to raising the children.

Also it is costy to raise a child in modern world and most of the parents have to work and cannot take good care of their chidren, and  entrust the big responsibility to their own parents, actually who are too old to give effective discipline to the minors. when they live together, the relationship of the whole family become more intricate and more conflicts conjure up,making life a sheer mess!

no one is silly enough to take these risks actively. those who are willing to have the second or third child must be at least rich enough to hire a nanny, to buy a  school adjacent apartment, and to be extremely confident in their marriage.

For me, i will never have the third child.