Since recent studies have argued that a pro-natalist effect could be obtained by introducing fertility-related pension systems for contrasting, especially in European countries, the plague of below-replacement fertility and the resulting problem of financing the widespread pay-as-you-go (PAYG) pension benefits, we built up an overlapping generations (OLG) general equilibrium model with endogenous fertility, to investigate whether and how a fertility-related pension reform increases population growth. We show that if the capital’s share in production is high enough, such a reform, in contrast with the suggestions of the preceding literature, always reduces the long-run fertility rate.