Population

Population growth tends to be beneficial for division of labor. The more laborers who are available, the more specialization is possible, since many specialists can, together, provide a wide range of products. Also, the more consumers there are, the more market niches may have a large enough customer base to become viable for someone to specialize in. As Henry Hazlitt points out, Robinson Crusoe must be a generalist, while the Swiss Family Robinson is able to have a father who hunts, a mother who prepares the food, and children who collect firewood. This produces a more efficient economy.

However, it appears that as death rates decline, people with the ability to reduce birth rates tend to voluntarily do so. In backward countries, production is so labor-intensive that families tend to have many children in order to accomplish the work needed to survive. It is not necessary to incur a great deal of expense for education before sending the children to work in the fields. In more developed countries, children tend to be more of a drain on parents' finances, and parents' accordingly limit their number of offspring. Of course, part of the reason for this may be that developed countries' governments also typically ban child labor, which renders children mostly unproductive until they reach the age of majority. In developing countries, child labor is an economic necessity, while in developed countries, it merely provides an additional, optional increase in the productivity of the economy. It is not clear that even if children in developing countries could work, that they would necessarily be put to much work, or choose to work much; even young adults, who legally can work, often choose to delay entry into the workforce while they pursue higher education. Bryan Caplan argues that modern parenting is more expensive than it needs to be, and that therefore the "price" of children is artificially high.

Environmentalists sometimes call for people to voluntarily limit their birth rates in order to protect the ecology of the planet. Benjamin Marks writes, "Those environmentalists who are upset at the fact that they are taking up space should go shoot themselves, and thereby practice what they preach and stop annoying the rest of us: a win-win situation."