The scrotum is the sac of skin located beneath the penis that holds and protects the testicles. The testicles are responsible for producing sperm, which happens most optimally at about 93.2ºF (5ºF cooler than the rest of the body). The scrotum moves closer to and further from the body, depending on environmental factors, to maintain that temperature.  Scrotal tissues also protect the structures inside the testicles.

What is the scrotum?

The scrotum is a sac of skin located under the penis. It’s divided into two sections and contains the testicles, epididymis (the coiled tube behind the testicles), and the spermatic cord (a structure that contains blood vessels, nerves, and the vas deferens).

Scrotum and male fertility

The scrotum helps protect the testicles. Its location outside of the body keeps testicular temperature around 2–8 °C below body temperature, which is important for sperm production. In order to regulate the temperature of the testicles, the scrotum moves up and down based on the temperature of a person’s body and the environment.

Research has shown that activities that warm the scrotum and testicles, such as taking a hot bath, bicycling, wearing tight-fitting underwear, or using a laptop computer on the lap, may temporarily damage sperm production and could affect fertility.

Certain conditions involving the scrotum can also affect fertility. These most commonly include:

• Varicocele. This is an enlarged veins in the scrotum, which studies have linked to increased scrotal temperatures and poorer sperm quality.
• Testicular torsion. This occurs when the spermatic cord twists, preventing blood from reaching one or both testicles. It’s an emergency condition that can cause extreme pain. If not treated quickly with surgery, torsion may lead to a testicle needing to be removed.
• Undescended testicle. In this condition, one or both testicles fail to move down into the scrotum in childhood, remaining instead in the inguinal canal space in the pelvis. This leads to increased testicular temperature and impaired testicle development. Early treatment via surgical correction is important to preserve fertility; up to 10% of those who have had one undescended testicle experience infertility. 
• Scrotal mass. An abnormal lump in the scrotum may resolve by itself, or may be caused by a condition like testicular cancer or testicular torsion. Depending on the cause, it may affect the testicles and fertility.

If you feel pain or swelling in your scrotum, it’s important to see a doctor promptly.