Intergenerational transmission of relative fertility and life course patterns

Abstract

The direct relationship between fertility and fertility behavior of mothers and daughters was examined. It was hypothesized that the relative propensity to control family sizes in 1 generation is transmitted to the following generation and that transmission of fertility levels across generations is in part a result of the transmission of specific fertility-determining life-course behaviors across generations. The data were derived from the Mormon Historical Demography projects set of computerized family geneologies. To assess the importance of cohort effects the completed fertility of 1st daughters and last daughters was compared by mothers completed family size and mothers birth cohort. Daughters who were the last born tended to have lower fertility than 1st born daughters. For 1st born daughters a positive association between mothers and daughters family size was confirmed. The distribution of mothers and daughters relative to the median births for their respective cohorts was examined. Each woman was allocated to 1 of 3 groups: low -- completed fertility was 2 or more children less than the median for all women in the birth cohort; medium -- completed fertility was equal to + or - 1 child from the median for other women in the same birth cohort; and high -- completed fertility was 2 or more children greater than the median for all women in the birth cohort. It was expected that a greater proportion of daughters than mothers would have relatively low fertility. For the 1830-39 cohort only 15% of the mothers had relatively low fertility but 25% of their daughters did; for other mother cohorts the comparisons were 15:26 18:26 and 15:23. It also was expected that the daughters of low fertility mothers would be more likely to have relatively low fertility. For low fertility mothers in the 1830-39 cohort 33% of daughters had relatively low fertility; 24% fell in the relatively high fertility group. The expected difference was found for the 1840-49 cohort of mothers and for the 1860-69 cohort but not for the 1850-59 cohort. It also was expected that the daughters of relatively high fertility mothers would have relatively high fertility. 33% of daughters with high fertility mothers in the 1st cohort had relatively high fertility; only 23% had low fertility. This pattern was consistent for each of the other cohorts of mothers. Tabular and multivariate analyses supported the strong possibility that both fertility behavior and indirect associations regarding timing of fertility-related life course events were transmitted intergenerationally. Cohort-specific influences were substantial. The analyses confirmed both the hypothesized intergenerational fertility association and the hypothesized cohort-specific effects.