[Limitations of reproduction medicine in male subfertility. Treatment of severe spermatogenesis disorders].

Treatment of severe male subfertility has become available since the intracytoplasmic injection of a single sperm into an oocyte was successfully applied for the first time in 1992. Moreover, also with the use of testicular spermatozoa for this procedure fertilization and pregnancies could be accomplished. This review addresses the development of these techniques and discusses achievements and problems as well as future aspects of the feasibility of early spermatid injection are stressed. Furthermore it includes the basic elements of spermatogenesis and the major concerns regarding the underlying genetic reasons for spermatogenic failure.