Fertility rates have been declining worldwide and most developed countries have fertility rates below the population replacement level. To a large extent, this change can be explained by the socioeconomic development. However, increasing fertility problems might play a role as well as there seems to have been a temporal decline in semen quality and an increase in male reproductive diseases like testicular cancer and genital malformations. These male reproductive problems are associated and in some cases proposed to be part of a testicular dysgenesis syndrome. This syndrome is hypothesized to originate in fetal life due to suboptimal androgen activity during a critical developmental period. Genetics may play a role in the development of the syndrome but the rapid increase in male reproductive disorders indicates that environmental factors, including endocrine disrupting compounds, are likely crucial. It is of great importance that the fertility trends are reversed as a fertility rate only slightly below the replacement level causes a significant decline in the population of women in the reproductive age within only a few generations.