The European Union just released 2004 data on ferility rates for the EU 25 countries. Here's the interesting chart:

Is this driving the results? Not necessarily. In a 2004 Journal of Population Economics paper, Alicia Adsera provided another explanation for the variation in birth rates: the structure of labor markets:

During the last two decades fertility rates have decreased and have become positively correlated with female participation rates across OECD countries. I use a panel of 23 OECD nations to study how different labor market arrangements shaped these trends. High unemployment and unstable contracts, common in Southern Europe, depress fertility, particularly of younger women. To increase lifetime income though early skill-acquisition and minimize unemployment risk, young women postpone (or abandon) childbearing. Further, both a large share of public employment, by providing employment stability, and generous maternity benefits linked to previous employment, such as those in Scandinavia, boost fertility of the 25–29 and 30–34 year old women.