One question prompted by the research was: How did China enforce the one child policy?
Until last year in China, after the first child was born in a family, the mother would have to be fitted with an IUD (intrauterine device), a device which would keep her from getting pregnant with a second child. While people in other countries may have had IUDs, the ones in China were made for a different purpose, to keep the population numbers under control, so they were created to be extremely hard to take out. If a parent wanted a second child, they would have to pay a large fine to keep the child, or they would have to abort the baby.
This issue is important because this policy was restricting the size of all the families in China.