The most common example of Malthus's theory (birth control) is generally known as One Child Policy introduced in China in 1979 due to overpopulation, which had been rapidly growing.
According to the policy, a couple is allowed to have only one child. If that child turns out to be a girl, they are allowed to have a second child. After the second child, they are not allowed to have any more children, except of ethnic minorities who are allowed to have three children in some cases. The one - child program is theoretically voluntary, but the government imposes punishments and heavy fines on people who don't follow the rules - when a woman gets pregnant second time, couple has to pay fee, depending on the region, from $370 to $12,800 (many times the average annual income for many ordinary Chinese), otherwise a woman is enforced to undergo abortion.
Although this policy has had a positive impact on the slowdown of population growth, it has caused vast inequalities among the society (benefits provided only for those who cooperated with One Child Policy, the male to female ratio in China lies at 117:100) and what is more, it violates the basic human rights.
2. The Conditions of Agricultural Growth: The Economics of Agrarian Change under Population Pressure
In contrast to Malthus, instead of scarcity of food supply, a Danish economist Esther Boserup emphasized the positive aspects of a large population.
In simple terms, Boserup suggested that agricultural methods and productivity of food depend on the size of the population - the more people there are, the more hands there are to work. Furthermore, she argued that as population increases, more demographic pressure is placed on the existing agricultural system, which stimulates invention and higher efficiency in use of land. It means that the changes in technology allow for improved crop strains and increased yields.
The main disadvantage of this positive theory is that, it is nearly impossible to implement Boserup's ideas into real life because this theory is based on the principle of closed society (migration was not considered).
From my point of view, none of these theories are completely correct and none of them are incorrect. On the one hand, it is likely that the population crash predicted by Thomas Malthus will occur in the future, but on the other hand, it is certain that the world will make enormous effort to develop new technologies and increase the productivity to feed the whole planet.