Clinical relevance of evaluation of sperm and ova.

The various methods currently available to assess the structural and functional fitness of the spermatozoa for the reproductive process have been reviewed. The semen analysis remains the single most important predictor of male fertility potential, even though sperm motility and morphology are inadequately and subjectively evaluated. Of the various tests used to assess sperm penetrating ability, the zona-free hamster oocyte penetration assay probably is the most useful and most widely used, especially to screen the penetrating competence of spermatozoa to be used for extracorporeal insemination procedures. However, several important limitations prevent it from being a definitive method for the assessment of fertility. The electron microscopic examination of the sperm as complementary to semen analysis and the zona-free hamster oocyte penetration assay is an important procedure, in that it permits a detailed assessment of the structural integrity, and hence the functional adequacy, of the various subcellular components that are responsible for cell motility, penetrating competence, and fertilizing ability. Unfortunately, the oocyte escapes analytical methods.