The rise of extramarital fertility and the intergenerational transmission of social status by means of birth weight

This paper examines the early sources of intergenerational status reproduction by investigating the effect of maternal level of education on child's birth weight. We analyze vital statistic data on all live births to single or married women in the Czech Republic in 1994, 1998, and 2002. We show first that the average birth weight did not change significantly between 1994 and 2002 and second that the effect of education level on birth weight grew quite significantly between 1994 and 2002. Three observations help explain these trends: single mothers' children have on average lower birth weights, the effect of maternal education on birth weight is much stronger among single than among married mothers, and the relative size of the population of single mothers grew significantly between 1994 and 2002. The changing structure of the population of mothers drives the trends. Once the composition of the population is standardized with respect to marital status of mothers, we observe a slight increase in the average birth weight and we see no change in the effect of mother's education upon birth weight. Hence, we conclude that while the basic principles of status reproduction did not change, there is nonetheless more status reproduction in contemporary Czech society as a result of the growing incidence of new family forms.