The testicles (or testes) are the male sex organs that make sperm and the hormone testosterone. The two testicles are located in the scrotum, a pouch below the penis.

Sperm start growing in the testicles. The sperm travel to the epididymis, where they mature. During ejaculation, sperm move out of both epididymides (plural of epididymis). From there, sperm move through both of the vas deferens tubes into the urethra (the tube that runs through the penis) and out of the body.