Essentials of Sperm Biology

Abstract

That the spermatozoon has a role in reproduction has been known for centuries, but the specifics of its contribution have only come to be understood in relatively recent times. Antoni van Leeuwenhoek was the first to describe “semen animals” (spermatozoa) in an ejaculate in 1677, and in 1679, he discovered the presence of spermatozoa in the vas deferens and testicular tissue, leading him to conclude that sperm production was the sole purpose of the testis (1). In 1683, he wrote that he was certain “that man comes not from an egg but from an animalcule in the masculine seed,” and in 1685, he concluded that each spermatozoon contained both a person in miniature and a persistent and living soul. This argument was in contradiction to Harvey’s and de Graaf’s hypotheses that it was the egg that contained the miniature and entire human, and the semen was merely the vehicle of a stimulating spirit that started the growth of the egg into the embryo.