The scrotum is a muscular structure that houses the testes. In order for normal sperm production to occur the testes must be a few degrees cooler than the rest of the body. For this reason the scrotum is positioned outside the body.
Fertility problems can develop if the testes do not descend into the scrotum within the first month or so after birth. Surgery can repair undescended testes, but permanent damage can result if the testes do not descend early enough.