The "ideal age for parenthood" and tempo-quantum interaction in Europe. Subnational regional age norms and the effects of first birth timing on second birth rates

Jan Van Bavel, Vrije Universiteit Brussel

Fertility differences in Europe are to a large extent due to parity progression after the first child: in countries with relatively high fertility, first birth postponement is to a large extent recuperated at higher ages with fast progression to a second child. This is less the case in countries with lowest-low fertility, where people end up with one only child more often. Using the third round of the European Social Survey, I investigate second birth rates in 23 countries to address the extent of timing-quantum interaction. I analyze the extent to which a delay of the transition to parenthood depresses the second rate and find that this postponement effect on second birth rates 1) is generally stronger for the highly educated than for the low educated; 2) that it is moderated by the national enrollment rate in formal childcare, but only for the higher educated; and 3) that it is strongly influenced by subnational regional ideas about "the proper age for parenthood". The focus of this paper is on the latter finding. We estimate an indicator for the ideal age for parenthood and see how it moderates the relationship between first birth timing and second birth rates across the NUTS1-regions of Europe. It appears that, the farther away the age at first birth was from the regional-cultural ideal, the lower the second birth rate subsequently is. This finding holds irrespective of whether the first birth occured before or after the ideal age. The findings also illustrate the continued relevance of the historical "Hajnal line".