Plenty of heirs, not enough dates

"The sex balance is seriously out of skew because of a strong cultural preference for boys and a population-control policy that limits most urban couples to one child and rural couples to two. There is also easy access to ultrasound machines and abortions, so when mothers learn they are pregnant with a girl, many are tempted to terminate and try again."

A better approach to population control would be for the government to just grow babies in jars and hand them out to families at random. The bonus with this, would be that every 1000th kid would be a genetically engineered super baby with special powers. The trade-off is that these babies probably wouldn't be quite as cute.