I was just about to say so. That's the whole reason the testes hang away from the body. Sperm cells form and survive best at just below body temperature. The scrotum then retracts or relaxes to pull the testes closer or allow them further away from the body as a way to regulate the temperature.
Yeah. I imagine there are people stupid enough to believe that laptop heat is enough to completely sterilize them and use that as birth control. Or dip their balls in hot water for a while.
*shudders*
*shudders*