what do the testes do in the reproductive system
NCI Dictionary of Cancer Terms Testes. The two testes (one of them is called a testis) are contained in a bag of skin called the scrotum. They have two functions: to produce millions of male sex cells called sperm.to make male sex hormones, which affect the way a man's body develops.he two testes (one of them is called a testis) are contained in a bag of skin called the scrotum. They have two functions: to produce millions of male sex cells called sperm.