[Exploration of pathological sperm and its fertilizing power]

The exploration of human sperms has considerably progressed during the last few years, side by side with the development of medically assisted procreation techniques. The sperms are explored by a battery of techniques which evaluate their functional state and the expression of their fertilizing power. Sperm count and motility assessment remain the basic examination in the exploration of couples' infertilities but other more sophisticated techniques can be used to evaluate certain stages in the fertilization process, including the recognition by, and attachment of the sperm to the zona pellucida of the oocyte, its penetration into this zone, the fusion of sperm and oocyte membranes and the transformation of the nucleus into a male protonucleus in the cytoplasm of the oocyte. Up to now, however, most of the techniques that evaluate the functional state of the sperm cell have not been predictive, and the only feasible and repeatable means of evaluating the fertilizing power of a semen is fertilization in vitro.