It is not surprising that so much investigation has been undertaken to establish the cause of childlessness, especially when the potentia coeundi of the male is not impaired. As long ago as 1957 the German Society for the Study of Fertility and Sterility was founded, embracing gynecology, andrology, and veterinary medicine. After its inception, meetings conducted in the spirit of its foundation were held every 2 years. This interdisciplinary, coordinated scientific work in the field of human reproduction achieved its value as a result of the stimuli provided by the permanent involvement of veterinary scientists. After about 20 years of activity, the Society adopted a highly differentiated pattern of work-directions in the field of human and veterinary medicine. Since 1976 annual meetings have been held on the topic of animal and human reproduction. These meetings have proved of great value, especially in the area of comparative medicine, and have led to excellent interdisciplinary associations. One of the most evident successes was the first extracorporal fertilization in humans with subsequent embryo transfer and full-term pregnancy. Gynecologists have found that in 40% of cases the cause of undesired childlessness rests with the male, and it is therefore no surprise that also in the field of andrology certain factors concerned with infertility have received great attention.