Illustration of a primary spermatocyte (centre), a cell which will divide and differentiate to produce sperm cells (spermatogenesis), inside a seminiferous tubule in a testis (testicle). Spermatocytes divide via meiosis to form spermatids, which in turn mature into spermatozoa, commonly known as sperm. Spermatozoa are the mobile male gametes (reproductive cells), which can fertilise the egg during sexual reproduction, and carry one set of chromosomes from one parent.