This chapter traces the history of the acquisition of knowledge about the spermatozoon. From the Greeks to today, writers and thinkers have been fascinated by the mystery of reproduction. Over the centuries, scientists, using the methodologies available to them, have discovered the role and both the normal and pathological structure of sperm. This cell, with its peculiar function, which is to fertilize the oocyte, is different from all the others because it shows motility needed to transfer genetic material to the embryo. The last part of this chapter addresses the problems associated with the advent of assisted reproduction and the biological perplexities that they have raised. New methodologies are also reported, such as the development of techniques to support in vitro spermatogenesis, the use of artificial intelligence and virtual reality, which could open up new scenarios in the study of reproduction.