Male patients referred for infertility problems are often curious as to whether their problem may be caused by environmental influences, and thus whether their chances of becoming a father can be increased by a change in lifestyle or occupation. The present level of knowledge does not allow a definitive, evidence based recommendation to be made. Except for some very few, rather extreme, occupational (e.g. 1,2-dibromo-3-chloropropane; DBCP) or iatrogenic (e.g. irradiation, cytotoxic drugs) exposures known to cause temporary or even permanent sterility, it is difficult to point to specific environmental influences as definite causes of male infertility. Nevertheless, recent research has generated some interesting information regarding the possible impact of the environment on male reproductive functions (1). This research was stimulated by reports on a possible time-related decline in male fertility (2)—a question still remaining controversial. However, there is now a considerable amount of information showing that environmental and lifestyle related exposure during early fetal development is of crucial importance for reproductive health in adult life (3).