The paper aims to show the way in which pension systems affect fertility rates. The author outlines the history of pension systems and traces changes in fertility. The article includes a brief overview of demographic theories and tells the reader why these approaches are inadequate in explaining fertility trends. In his analysis, Zwierzchowski makes use of the overlapping generations model (OLG) to show why and under what circumstances pensions may discourage people from having children. After further theoretical research, the author concludes that the negative influence of pension systems on fertility could be neutralized by the introduction of a public assistance program targeted at parents. The costs of such a program could be covered by those who do not have children, Zwierzchowski says. While today’s welfare state systems cover some of the costs of bringing up children, it is unclear to what extent this assistance neutralizes the negative impact of pension systems on fertility, Zwierzchowski notes.