The testes (testicles) are 2 small organs that are found inside the scrotum. The testes are responsible for making sperm and are also involved in producing a hormone called testosterone. Testosterone is an important hormone during male development and maturation for developing muscles, deepening the voice, and growing body hair. The scrotum is the bag of skin that holds and helps to protect the testicles. The testicles make sperm and, to do this, the temperature of the testicles needs to be cooler than the inside of the body. This is why the scrotum is located outside of the body.