Final answer:
China's one-child policy, while effective in reducing population growth, led to gender imbalance and an aging population. Alternative approaches to controlling population growth have been suggested, and the United Nations continues to monitor projected global population changes.
Step-by-step explanation:
The one-child policy in China was introduced in 1979 to curb the population growth that was seen as a threat to China's economic and environmental stability. While the policy has been effective in lowering the growth rate from 3.2% in 1964 to about 0.5% today, it has also led to severe side-effects and future consequences. Female infanticide, an increase in the number of abortions, and a significant gender imbalance with a cultural preference for male children are among the complex social issues that have emerged. Additionally, the strict enforcement has led to a rapidly aging population and a potential future shortage of young workers.
There have been instances of underreported births and persistent population growth despite the policy, which led to its eventual relaxation in 2015. The policy's impact was also questioned as fertility rates were already declining when it was implemented. Alternative strategies to population control, such as improving health, education, and employment opportunities for women, have been suggested as more humane methods and have been successful in other countries. Notably, the global understanding remains that unchecked population growth is ultimately unsustainable, and the United Nations predicts significant variances in world population by 2100.