Demographic and Genealogical Analysis of the Population of Toulal (Meknes, Morocco): Family Structure and Inbreeding

This study presents a demographic and genealogical analysis of the Aït Saâdallah community of Toulal (Meknes, Morocco), composed of the Aït Messaoud and Aït Ouaârab factions. Genealogical data from 1533 individuals born between 1850 and 2015 were analyzed. Demographic parameters included family size, parental age at first birth, spousal age gap, intergenetic intervals, lifespan, kinship structure, and inbreeding coefficients. The mean number of children per individual was 4.17 ± 2.40. Men and women had similar average numbers of boys (2.43 ± 1.47) and girls (2.45 ± 1.50). The average age at first birth was 28.5 ± 5.6 years for men and 20.9 ± 3.6 years for women, with a mean spousal age gap of 8.95 ± 3.85 years. The intergenetic interval averaged 3.13 ± 1.96 years. Mean lifespan was 66.2 ± 18.9 years and was significantly higher in women than in men (P P < 0.001) but not by sex. A gradual increase in inbreeding was observed across generations. Overall, the Aït Saâdallah population exhibits high fertility, sex-related differences in lifespan, strong kinship cohesion, and moderate but increasing inbreeding, reflecting long-standing demographic and matrimonial traditions within this Amazigh community.