Looking for the causes of the increasing gap in intra-metropolitan fertility: the Spanish case

This paper analyses the causes of geographical fertility differences within metropolitan areas, by focusing on the metropolitan regions of Barcelona and Madrid. Our main hypothesis is that fertility differences among municipalities would be based on two main elements: 1) the degree to which the suburbanization process has developed –which, in the Spanish case, has rapidly expanded and has been highly selective– and 2) foreign immigration’s local level impact. Results from the descriptive analysis show that despite regional fertility levels have become increasingly similar within Spain, there are increasingly strong fertility variations within Barcelona and Madrid metropolitan regions. While the core cities have low, late and more stable fertility levels, the suburban periphery municipalities have earlier and higher fertility levels. This would confirm the fact that different areas within the metropolitan regions are increasingly specializing in a particular function –productive or residential. These settlement preferences are in turn dependent on nationality and the life cycle stage. Factor analysis using Movimiento Natural de la Población (vital statistics) data allow us to investigate the causes of such differences.