Full Sperm Production in the Testicle Description
[Continued from above] . . . intercourse.
Each sperm takes about seventy-two days to mature and its maturity is overseen by a complex interaction of hormones. The scrotum has a built-in thermostat, which keeps the sperm at the correct temperature. It may be surprising that the testicles should lie in such a vulnerable place, outside the body, but it is too hot inside. The sperm production needs a temperature that is three to five degrees below body temperature. If it becomes too cool on the outside, the scrotum will contract to bring the testes closer the body for warmth.