A Contribution to the Economic Theory of Fertility

We show that a non-separable formulation of preferences that allow for a low EIS but a high Elasticity of Intergenerational Substitution (EGS) can simultaneously account for the evidence of declining demand for children and increasing demand for longevity as income increases. The model with a single elasticity cannot account for both. Our results suggests a major role for a new parameter in macro, the EGS. While the EIS mostly influence short term economic decisions, the EGS influence mostly long term economic decisions.