The testis is a male reproductive organ responsible for producing sperm and hormones, primarily testosterone. Typically, males have two testicles, which are located in the scrotum, a pouch of skin outside the body. This external positioning helps regulate temperature, which is crucial for sperm production. Each testis contains seminiferous tubules where sperm cells are generated through a process called spermatogenesis. The testis also produces hormones that play a vital role in the development of male secondary sexual characteristics, such as facial hair and a deeper voice, during puberty.