Endogamous marriages are those that occur between spouses who are related by blood. In Senegal, most endogamous marriages are between paternal and maternal cousins. The 1986 Senegalese Demographic and Health Survey data reveal that women first marrying do so with paternal or maternal cousins or other relations. About 70 percent of married women are related to their husbands. This pattern has not changed much since 1970, although there are variations among ethnic groups. The lowest prevalence of endogamous marriages (50% to 60%) are found among the Manding and Diola, who live in the southern and Eastern parts of the country, while the highest levels (between 65% and 80%) prevail among the Wolof, Pulaar, and Serer. In most cases, women are married to paternal cousins, except among the Serer, where preference is given to maternal cousins.
In Senegal, endogamy cannot be explained by the matrilineal or patrilineal nature of the society. One purely demographic factor is the large age differences between spouses. Another important factor that encourages and sustains endogamous marriage is the permanent quest for cohesion and close ties between families, which in turn contributes to marriage stability.