Age at marriage as a variable in socio-economic differentials in fertility

Earlier studies have pointed out that socio-economic differentials in fertility depend upon both religion and farm background. These studies report a negative relation between fertility and socio-economic status for non-Catholic American couples in contrast to a positive relation for Catholics. Likewise, a negative differential for American couples with farm background has been observed in contrast to no differential for twogeneration urbanites. Age at marriage is a third such interaction variable: the strong negative socio-economic differential observed when wife’s age at marriage is under 19 diminishes with advancing age at marriage and becomes positive for wives who married at age 23 or older. Moreover, for both non-Catholics and Catholics, couples with and without farm background, the differential by wife’s education is negative when wife’s age at marriage is young, positive when her age at marriage is old. Both sociological factors (the incidence of non-familial adult roles) and differential fecundity appear to underlie the interaction. The analysis is based on reports of once-married, white, nonfarm wives aged 30 to 39 included in the 1955 or 1960 Growth of American Families Studies or the 1965 National Fertility Study (approximately 1,000 in each survey).