A Reformulation of the Economic Theory of Fertility
利他父母通过最大化跨代效用函数选择生育和消费，推导出生育率与全球实际利率、利他程度、儿童存活率正相关，与技术进步率、社会保障增长率负相关。
Altruistic parents choose fertility and consumption by maximizing a dynastic utility function. The maximization implies an arbitrage condition for consumption across generations, and equality between the benefit from an extra child and the child-rearing cost. These conditions imply that fertility in open economies depends positively on the world's long-term real interest rate, the degree of altruism, and the growth of child-survival probabilities; and negatively on the rate of technical progress and the growth rate of social security. The growth of per capita consumption across generations depends on changes in the child-rearing cost, but not on interest rates or time preference.