Many of the world’s poorest and least productive societies have the largest families. That fact does not prove that housing, childcare, or wages are irrelevant in rich countries. It does prove that low income alone does not prevent high fertility. People have children under material conditions far harsher than those usually described as making children “unaffordable” in the developed world.
High fertility is now concentrated mainly in sub-Saharan Africa. In 2024, 13 percent of countries and areas still had fertility of four or more children per woman, mostly in that region. Their populations are young, childbearing begins earlier, and a long span of reproductive exposure makes several births possible without deliberate planning for a large family.
Early marriage is central. Globally, 76 percent of first births to mothers under eighteen occur within marriage, though regional patterns differ. In 2024, eighteen countries—all in sub-Saharan Africa—had adolescent birth rates above one hundred births per thousand girls and young women ages fifteen to nineteen. Earlier first births leave time for more births and often interrupt education that would have changed both opportunity costs and family preferences.
Lower contraceptive use matters directly. Among women in sub-Saharan Africa who wanted to avoid pregnancy, modern-method use rose from 29 percent in 1994 to 57 percent in 2024. The gain is large; it also leaves a wider gap than in most wealthy regions. Some women want more children. Others face unmet need, partner opposition, or weak services. High fertility therefore combines intended large families with births women would have preferred to delay or avoid.
Why children have a different economic place
In an agricultural or informal household, children can contribute work and support parents in old age. They remain costly and dependent for years, but the flow of resources across a lifetime differs from a child in a city who requires two decades of concentrated investment before becoming economically independent. Where pensions and savings are unreliable, kin are a form of security.
Child mortality also shapes behavior. When survival is uncertain, parents may have additional births partly because they cannot assume every child will live to adulthood. Falling mortality usually precedes falling fertility, creating the rapid growth described in Chapter 001. As survival becomes more reliable, desired family size and the number of “insurance” births can decline, though culture and institutions adjust with a lag.
Kin networks distribute costs differently. Older siblings and grandparents may provide care; multigenerational living reduces the need to purchase a separate bedroom and formal childcare for every child. Motherhood can also bring adult status earlier and more visibly than education or paid work. A large family may signify continuity and standing rather than a failure to optimize consumption.
There is nothing romantic about the hardships surrounding some of these births. Early marriage can deprive girls of choice. High fertility combined with weak medical care raises risks for mothers and infants. Children may work because a family has no safe alternative. Old-age dependence on children can burden both generations. The comparison should not turn deprivation into a pronatalist model.
It should make affluent excuses more precise. A couple in Boston is not poorer than a family in Niger. They face a different arrangement of costs: expensive urban space, high foregone earnings, and weak kin support. Motherhood also brings less status than professional achievement. “We cannot afford children” often means “we cannot have children without giving up the life our society taught us to expect.” Sometimes that sacrifice really is too large. Sometimes the expectation deserves examination.
The conditions that permit many births are not necessarily the conditions in which mothers and children flourish. A humane pronatalism should want both: enough confidence and support for families to welcome children, and enough health and material provision for those children to thrive. Poor high-fertility countries show that wealth is not sufficient and poverty is not prohibitive. The social meaning of a child and the network around a mother can outweigh income itself.
Citations
- United Nations Department of Economic and Social Affairs, “The New Landscape of Fertility and Family Planning 30 Years After Cairo and Beijing”, Policy Brief No. 172, 2025.
- United Nations Department of Economic and Social Affairs, World Fertility 2024, 2025.
- United Nations Department of Economic and Social Affairs, World Fertility and Family Planning 2020: Highlights, 2020.