Preferences, including preferences for children, are shaped during the formative years of childhood. It is therefore essential to include exposure to religious practice during childhood in an attempt to establish a link between religiosity and fertility. This path has not been explored in the documented literature that looks at the relationship between current religiosity and fertility. The International Social Survey Programme: Religion II (ISSP) provides the data base. It includes information on maternal/paternal/own mass participation when the respondent was a child (nine levels each), as well as on his current churchgoing (six levels) and prayer habits (eleven levels). These variables are included as explanatory variables in ‘fertility equations’ that explain the number of children of Catholic women in Spain and Italy. The core findings are that exposure to religiosity during the formative years of childhood, has a pronounced effect on women’s ‘taste for children’ that later on translates into the number of her offspring. In Spain, the two parents have major opposite effects on women. Most striking is the negative effect of the mother’s intensity of church attendance on her daughter’s fertility: Women who were raised by an intensively practicing mother have on average one child less that their counterparts who were raised by a less religious mother. On the other hand, an intensively practicing father encourages the daughter to have more children (by about 0.8, on average). The Italian sample confirms the statistically significant negative effect of the mother’s religiosity. The father’s religious conduct has apparently no effect on Italian women’s birth rates. Current religiosity seems to be irrelevant, both in Spain and in Italy. It follows that religiosity and fertility are interrelated but the mechanism is probably different from the simplistic causality that is suggested in the literature.