[Fertility assessment based on sperm examination].

Male fertility is indirectly evaluated by analysis of semen. Two questions must be answered in connection with an investigation program. 1. Which prerequisites must the spermatozoa fulfill to the fertilization of oocytes in vivo and to the induction of a normal embryogenesis? 2. Which laboratory tests can be taken as an in vitro model for the fertilization process? Fertilization consists of various steps which require different spermatozoal functions. Several methods were developed to test in vitro whether the semen sample is capable to realize the sequence of fertilization, whereas, it is supposed that there is a close connection between the laboratory test in vitro and the fertilization in vivo. The methods of sperm analysis are presented and their medical practice and predictive value is discussed.