There is a naive view that the problem of rapid population growth can be effectively solved if enough money is invested in family planning services. But it is no accident that the world's highest population growth rates are in poverty-stricken sub-Saharan Africa. Child mortality in this region remains stubbornly high, so it makes sense for women to have lots of children to ensure that at least one son survives into their old age. Children are also economic necessities for peasant families engaged in traditional agriculture: in many systems, the larger the family, the more land is allocated to it. It follows that only by reducing the demand for large families through economic development can the problem of overpopulation be solved.