Final answer:
Spermatogenesis is the process that marks the beginning of viable sperm cell production, starting with spermatogonia and resulting in mature sperm cells after several stages of cell division and development.
Step-by-step explanation:
The beginning of viable sperm cell production is called spermatogenesis. This process takes place within the seminiferous tubules of the testes, starting with a diploid stem cell known as a spermatogonium. Spermatogonia divide by mitosis to produce primary spermatocytes, which then undergo meiosis to become secondary spermatocytes. These haploid cells, after a second meiotic division, become spermatids, which will eventually develop into mature sperm cells capable of fertilization. The maturation process, when a spermatid develops a flagellum and becomes a sperm cell, signifies the end of spermatogenesis and takes approximately 9 to 10 weeks to complete.