Firstborn Daughters and Family Structure in Sub-Saharan Africa

Does the absence of missing baby girls in sub-Saharan Africa imply a lack of son preference in the region? This paper uncovers systematic gendered effects on family structure and fertility in sub-Saharan Africa. Using data from Demographic and Health Surveys, we show that having a firstborn daughter, rather than a son, significantly influences women’s family dynamics. Women with a female firstborn experience higher long-term marriage rates but are less likely to marry the child’s father when the birth occurs prior to formal union. They also face higher divorce rates and greater likelihood of entering polygamous unions. Despite these marital transitions, they tend to have more children. Our analysis further reveals that having a firstborn daughter is associated with poorer living standards and adverse health outcomes for mothers. To examine the mechanisms driving these patterns, we employ a geographic regression discontinuity design along ancestral ethnic borders separating matrilineal and patrilineal traditions. This approach highlights patrilineality as a key driver, shaping both marriage dynamics and fertility.