outside the body. The spermatogenesis is less efficient at lower and higher temperatures than 33 °C. Because the testes are located outside the body, the smooth tissue of the scrotum can move them closer or further away from the body. The temperature of the testes is maintained at 34.4 °C, a little below body temperature, as temperatures above 36.7 °C impede spermatogenesis. There are a number of mechanisms to maintain the testes at the optimum temperature.

The cremasteric muscle covers the testicles and the spermatic cord.