Spermatogenesis is the process by which male spermatogonia develop into mature male gamete, spermatozoa. It starts at puberty and usually continues uninterrupted until death, although a slight decrease can be discerned in the quantity of produced sperm with increase in age. The process of spermatogenesis includes the formation of spermatogonia from germinal epithelium (primordial germ cell) through mitosis (multiplication phase). Finally they stop undergoing mitosis, grow and become primary spermatocytes (growth phase). Each spermatocyte undergoes meiosis (maturation phase). First maturation division is reductional, and produces two secondary spermatocytes. The latter divides by equational division (second maturation division) to form four haploid spermatids. Spermatids receive nourishment from the Sertoli cells to form sperms. This step is called spermiogenesis.

During this process one spermatogonium produces four sperms having half number of chromosomes.