Socio-economic factors influence reproductive behaviour negatively. In addition, couples postponing childbearing into later phases of life jeopardize their changes for parenthood. Other medical reasons including the alleged "sperm crisis" are less likely to lead to declining birth rates. According to several studies, fecundity has remained stable or increased over the past decades.

Birth rates, Contraception, Fecundity, Fertility, Infertility, Reproductive age, Sperm crisis
hdl.handle.net/1765/90833
Journal fur Reproduktionsmedizin und Endokrinologie
Department of Public Health

Nieschlag, E, & te Velde, E.R. (2010). Why have birth rates dropped? For medical reasons?. Journal fur Reproduktionsmedizin und Endokrinologie (Vol. 7, pp. 403–406). Retrieved from http://hdl.handle.net/1765/90833