The Male Reproductive System Penis Testes Glands Vas Deferens Urethra Scrotum Sperm cells Temperature Semen The male sex cells are the _______ _____. Sperm cells are made in the _________. The testes are held outside the body in a bag of skin called the ___________. This keeps the sperm at the right ___________. Sperm travel up the _______ ________ where liquids are added from the ________. This mixture is called ________. Semen flows out of the _________ through a tube called the ___________