Abstract ：
Recent research has indicated that the human infertility rate is increasing. This study tests the hypothesis that this change results from increasing pollution stock, which consequently damages the reproductive health of individuals. Individuals can choose the number of their children without worrying about pollution effects when the pollution stock is small. Nevertheless, when the pollution stock becomes great relative to reproductive health capital, it starts constraining the number of children that individuals can bear and rear. Reduced childrearing time enables young workers to work longer and to earn more, consequently boosting economic growth, although such a constraint might retard economic growth temporarily. The accelerated physical capital accumulation in turn increases pollution stock, thereby lowering the fertility rate more. On a balanced growth path, the fertility rate remains constant over periods, but the fertility rate might be lower than the population replacement rate. Pollution abatement measures raise the fertility rate by reducing pollution damage to reproductive health. Although the long-term growth effect of the pollution tax changes is ambiguous, the balanced growth rate after the tax changes is lower than the balanced growth rate without fertility constraint binding.

Keywords: fertility, human infertility, pollution stock, reproductive health capital
JEL Classification: H23, J11, J13, Q54, Q56, Q58

Declaration of conflict of interest: The author has no competing interest or personal relation to this study

Data availability: The author does not analyze any dataset.

Funding information: Japan Society for the Promotion of Science (KAKENHI grant No. 25K05125)