When prescribing systemic therapies, physicians should always be aware of the risk to impair male fertility. At the same time, the question of existing and future desire for children should be actively addressed. Unfortunately, there are no databases that provide information on the impact of medicines on male fertility; thus, an intense literature review is often required. In general, data of drug-related adverse effects on male reproduction are sparse; most often no human studies have been performed. Conclusions are frequently drawn from animal toxicity studies within the approval procedure. By law, physicians are requested to explain potential gonadotoxic effects to the patients and to discuss fertility-preserving options.