Sperm cells, or spermatozoa, are the male reproductive cells in many organisms, including humans. They are produced in the testes through a process called spermatogenesis. Each sperm cell has a head, which contains genetic material, a midpiece packed with energy-producing mitochondria, and a tail, or flagellum, that helps it swim toward the egg. The primary function of sperm cells is to fertilize the female reproductive cell, or ovum, to create a new organism. Sperm cells are typically motile, allowing them to navigate through the female reproductive tract to reach the ovum. Successful fertilization can lead to the development of an embryo.