Historically, there is clear evidence of an inverse relationship between female labour supply and fertility. However, the relationship across countries is now positive. Countries like Germany and Italy, with the lowest fertility, also have the lowest female participation rates. This paper analyses the extent to which this can be explained by public policy, in particular taxation and the system of child support. The results suggest that countries which have individual rather than joint taxation, and which support families through child care facilities rather than child payments, are likely to have both higher female labour supply and higher fertility.