The theory of consumer choice explains the relationship between the preferences and the expenditure done by the consumer. In other words, it explains how consumer prefers to maximize the utility subjected to the budget constraint.

The microeconomic theory of fertility is related to the theory of choice in a way that before planning the child, parents too analyze the cost and benefits of the child they will give birth to.

Yes, economic incentives and disincentives can influence the size of the family. For example, in the countries such as Nordic countries, where the economy is expanding but the population is less as per the need, government provide incentives such as maternal and paternal leave, free or subsidized necessary childcare products. This motivates people to have a large family. Also, it reduces the prejudices towards girl child as most of the people have in Asian and African countries.

But, in case, if the government disincentivizes the people to have a large family such as the Chinese government, then it discourages people to have a large family. But it also increases the chances of having illegal children in the country. Some critics argue that the one-child policy of China has resulted in increasing the number of children which the government does not have any record. It is because family and hospitals settle the deal in exchange for money. This increased corruption in the economy.