Although the one-child-policy has skewed the population demographics, there is another problem waiting to happen.
Many single kids are brought up by their grandparents who spend money and a lot of time on them. This is so the parents can make something of a career for themselves and possibly pay the mortgage too. This maybe what causes the 'little prince/princess' label.
However, now that families can have 2 kids, there may be a bit of a problem for grandparents to handle 2 kids, plus it costs twice as much too.
Also, granny knows about kids, but mum and dad dont know anything. Once the granny generation dies, who knows about kids then? Who is there to look after the kids? The parents wont, because they were only children, brought up by grandparents and they have good careers.
Can you see what I am getting at? As far as I can see, there will be a big, big boom in child day care who market themselves as knowing what to do, but don't. Typical 25 year-olds, working for a Chinese company, often do not get home until 10.30pm, so how will this play out in the lives of their kids?
China has a very steep learning curve ahead for itself.
As with all things, the pendulum fully swings to the right, then to the left as a reaction, eventually we all hope to learn from the extremes.