The sperm count has proved to be one of the first examination performed in evaluating the fertility of a couple. It has been possible to establish a few standardized norms from the sperm count of fertile men, but, except for azoospermia, there is no specific limit beyond which it is possible to confirm the absence of fertilization of a sperm. The various criteria of the sperm count then examined, emphasizing the importance of studying the morphology, on optical as well as electron microscopy, since it is the spermatozoid's morphology as well as their mobility that differentiate fertile man from infertile ones. Any abnormality often severely compromises the ability to fertilize spermatozoids.