Population control? One-child policy? Two-child policy?

As we know, China has implemented a one-child policy in an effort to control its population. I just read an article that between now and 2050, its population will remain fairly close to 1.3 billion with little change. On the other hand, India will surpass China, and the global population in 2050 will be around 9.4 billion. If the entire world were to establish a one-child policy, then if we look at China's results, it would prevent the world from overpopulating. But we also see negative side effects of the one-child policy. Parents prefer boys over girls, and this would create a gender imbalance. With only one child in the family, the parents will spoil them into little brats. What about a two child policy? This would give parents the opportunity to have one boy and one girl, yet it still helps keep the world from overpopulating. It is of course controversial in matters of human rights, but do you think it is worth it?