The testicles are the male reproductive glands, where sperm and testosterone (the male sex hormone) reproduced. The testicles are the two oval-shaped glands that sit inside the scrotum.

The scrotum is made of skin and thin muscle, and it contains the testes (also called testicles), as well as many nerves and blood vessels. The scrotum changes size to regulate the temperature of the testes.

The testicles are suspended away from the body to keep them cooler than internal organs. Semen is produced in the testes and stored in the epididymis. The prostate gland and seminal vesicles secrete fluids that nourish and protect the sperm.

The epididymis (a long, coiled tube) stores and transports sperm from the testes to the seminal vesicles to the urethra, ready for sexual intercourse.