This chapter presents an endogenous fertility model that incorporates human capital accumulation and monetary policy within a closed economy. It subsequently examines how fertility, education investment for children, and the inflation rate are affected. The results of the theoretical analysis indicate that child allowances increase fertility but reduce educational investment. However, the effect of subsidies for educational investment on fertility and educational investment is ambiguous due to the closed economy context. Changes in fertility and income growth can influence the inflation rate through childcare policies. Additionally, an increase in the monetary stock policy promotes human capital growth by facilitating physical capital accumulation.