death (Korang-Okrah and Haight, 2015). In Rwanda, where the land registration intervention formalized women’s inheritance rights in the event of their husband’s death, we find no positive fertility impacts.

Taken together, our results suggest that a key driver of fertility in Sub-Saharan Africa is women’s use of childbearing as a strategy to ensure future access to land and income. Given the common age gap between spouses in Africa, widowhood is a likely eventuality that can be anticipated from a young age. In patrilineal contexts where prevailing norms exclude women from property ownership and inheritance, having a son who is entitled to inherit from his father can mitigate a woman’s risk of housing and land dispossession upon her husband’s death. The costs of this risk are significant: using data from Mali, Van de Walle (2013) shows that widows in Mali are worse off in a number of dimensions, even after they are absorbed into other households. Furthermore, in patrilocal contexts where the practice is for daughters but not sons to move away upon marriage, women are more likely to rely on their sons in old age than on their daughters. In particular, our study suggests how— in the face of weak inheritance rights and limited availability of formal pensions—women’s demand for children results from their need for security in old age.

To the best of our knowledge, our study is the first to estimate the causal impact of an increase in women’s earnings on fertility in a high-fertility, low-income setting. Previous studies have shown that providing young girls with the opportunity to have a paid job delayed their marriage and childbearing (Jensen, 2012; Heath and Mobarak, 2015). However, these studies could not disentangle the effect of an exogenous increase in income from the effect of accessing the labor market for girls who may not have worked otherwise. In the present paper, we study women who are already married and working, which allows us to isolate the impact of an increase in income. Moreover, though previous studies have estimated the impact of unconditional cash transfers and found null or negative effects on pregnancies (Baird et al., 2011; Palermo and Hjelm, 2016), these impacts have mostly been among young women. Furthermore, the transitory and unearned nature of the income received through cash transfers could potentially have different effects.

Our findings are consistent with previous theoretical insights on old-age security motives for fertility (Becker, 1960; Cochrane, 1975; Nugent, 1985; Lindo, 2010; Werding, 2014; Hackman and Kramer, 2021). They also contribute to the limited empirical literature on the topic. In Sub-Saharan Africa, a region where the role of children as investment goods is particularly salient due to the relative lack of formal pension systems and old-age insurance, the literature includes a quasi-experimental study showing a negative fertility response to the expansion of a pension program in Namibia (Rossi and Godard, 2022), an observational study in Senegal showing how demand for sons is a strategy to cope with widowhood (Lambert and Rossi, 2016), and widespread evidence of a pattern of increased son preference in places where only males inherit land (Filmer et al., 2009; Fuse, 2010; Rossi and Rouanet, 2015; Eliason et al., 2018; Boonaert et al., 2021). We complement this literature by showing how women’s lack of inheritance rights over household land is an important driver of women’s fertility responses across a range of Sub-Saharan African countries.

Our results run counter to simple opportunity cost models of fertility, which predict that an increase in female earnings will decrease fertility by increasing the opportunity cost of having children (Butz and Ward, 1979). Empirical support for this model comes mostly from high-income countries (Butz and Ward, 1979; Schultz, 1985; Heckman and Walker, 1990), 2