To some extent, the success of the one-child policy in controlling the population growth in China depends on your definition of "success."
The one-child policy was introduced in 1978. According to the Chinese government, over 400 million births have been prevented since that time, which is a significant reduction. The fertility rate in China possibly would have declined to some degree during that time period without the official policy, as have the fertility rates in many countries experiencing increasing urbanization and other social changes.
The policy has been met with opposition by human rights advocates. It has also created a generation of parents who have only one child to carry the responsibility of caring for their needs as they age.
Population control policies in China generally revolve around the one-child policy enforced by the Chinese Communist Party (CCP). The policy aims at controlling population booms by limiting each couple to one child. While such a campaign has been successfully implemented in urban cities, the same situation cannot be said to have been replicated in rural areas. There is a tendency for rural inhabitants to have more children to serve as additional helpers and labour on farms. Since males are the only ones who can inherit the family line in Chinese society, couples are also more likely to continue trying out for more children to bear a son. Such a preference for boys has led to female infants being neglected, abandoned or even killed in acts of infanticide, resulting in a severely unbalanced male-to-female ratio. Furthermore, since most families are only allowed to have one child, they usually concentrate all their efforts into bringing up that one individual. This has led to the emergence of a whole generation of Chinese youths who are spoiled in nature and are used to having their every whim and fancy met by their parents. Concerns have, however, emerged recently over the fact that the one-child policy may in fact have worked too well in China, leading to the rise of an aging population.