Human sperm-oocyte recognition and infertility

The incidence of infertility related to both male and female factors contin ues to rise despite many advances in reproductive technologies. Some abnorm alities in human gamete interaction have been shown to be due to defects in the sperm, and others have been attributed to defects in the zona pellucid a (ZP). Our lack of understanding of molecular mechanisms involved in the i nteraction of human sperm with the ZP infertile as compared with infertile females and males has been limited because of the unavailability of human o ocytes and ethical restraints on experimental studies. It is becoming incre asingly apparent that improved clinical assays are necessary for evaluating sperm-ZP interaction in order to assess the optimal procedures for success ful fertilization and pregnancy. With advances in molecular biology, the ge nes encoding the three major human ZP proteins have been identified and com plementary DNAs are available to begin to better evaluate the molecular bas is of sperm-ZP interaction.