AbstractThis paper tests, within the framework of LISREL, the causal structures of fertility using data from the 1973–74 Growth of Alberta Family Study (GAFS) of women aged 18–44 who are currently married or living common‐law. Differential fertility among two groups of women classified by nativity also are examined. The women's background characteristics (e.g., age, religiosity, and education) are viewed as exogenous variables. The endogenous variables are familism and expected family size; familism is designated as an intermediate variable in the model, linking demographic and socioeconomic (including cultural) factors to fertility. The results indicate that familism acts as an important variable explaining fertility, particularly, among foreign‐bom women. The study confirms and extends earlier research findings that religiosity and education influence couples’ fertility, the former positively and the latter negatively.