Introduction In recent years, researchers have postulated a decreasing fertility potential of males and a rising incidence of testicular malignancies. Materials and methods In this retrospective observational diagnostic multicenter study, 302 patient files of subfertile men whose testes were biopsied for TESE procedure were analysed. All patients referred to reproductive medicine centres in Northern Germany and they were identified by the cycle data collected by the German IVF register. A total of 280 patients (436 cycles) treated for intracytoplasmatic sperm injection after TESE procedures were eligible to be analysed. Results Our findings: 13.0% overall paternity rate before TESE procedure, 45.9% smokers, maldescensus testis was found on occasion (12.9%), and mumps orchitis previously occurred to 10 patients (3.6%). The tumour incidence rate at the time of testicle biopsy was 1.81% (= 5 pts.). Two of these patients had an anamnesis for maldescensus testis and one patient acquired mumps orchitis in childhood. Conclusion Our data even reflects that tumour patients express an interest in having children after completion of cancer treatment, presenting four patients who had testicular biopsies after a previous malignancy. Moreover, there is evidence suggesting that environmental factors are causative for the trends in occurrence of male reproductive health problems. Within our highly selected population, the testicular tumour incidence rate is 100-fold higher than in a standard population. Supposing that the incidence rate of testicular malignancies among infertile men continues to increase in comparison to the incidence rate of the general male population, one has to count on an incremental number of males suffering from subfertility and testicular tumours.