The testicles are oval-shaped organs covered by a pouch of skin called the scrotum. They’re also referred to as the testes.

The testicles are held in place by spermatic cords, which are made of muscle and connective tissue. The testicles’ main job is to produce sperm and the hormone testosterone.

Normally, each testicle is about 2 inches long, though it’s not unusual for one testicle to be slightly larger than the other. They start to grow around age 8 and continue to grow until the end of puberty.

If your testicles grew to a larger than average size, you may experience no health-related issues or other complications.

But one 2013 study published in the Journal of Sexual Medicine suggested that larger testicle volume is associated with a higher risk of cardiovascular disease. The study didn’t explain the possible connection, though. More research is needed to better understand this possible relationship.

Having large testicles is also associated with greater sperm production and higher levels of testosterone, as well as higher levels of aggression. Conversely, other research suggests are associated with lower levels of sperm production.

Researchers have also found that men with smaller testicles tend to be more nurturing fathers. On average, they also have lower levels of testosterone.

If your testicles appear to have grown larger, it could be the result of swelling caused by a medical issue. Some of these issues are minor and temporary. Others may be serious enough to require surgery.

Testicular cancer may be the most well-known condition affecting the testicles, but it’s only one of several possible explanations for growth or swelling in that area.

If you have concerns about your testicles or any aspect of your reproductive health, see a urologist. A urologist is a doctor who specializes in the urinary tract (for men and women) and the male reproductive system.

You may be in perfect health, but having reassurance from a physician may provide some peace of mind.

As you age, your testicles may grow smaller (atrophy) somewhat. Your scrotum may hang lower than it did when you were younger. These are normal changes.

But if you notice other changes to the size or feel of your testicles or scrotum, get a doctor’s evaluation to rule out any possible health conditions.

In addition to protecting the testicles, the scrotum also serves as a means of maintaining an optimal temperature for sperm production.

When the testicles are too warm or too cool, the quality of the sperm they make suffers. As a result, the scrotum changes shape and size in response to temperature changes.

When taking a hot shower, you may notice your scrotum hangs lower to be surrounded by more air and avoid overheating. When it’s cold out, the scrotum pulls upward toward the body to help keep the testes warmer.

If your scrotum seems larger than normal or if it seems to have become swollen recently, see your doctor.

Here are some conditions that can cause scrotal swelling:

Hydrocele

A hydrocele is a buildup of fluid around the testicles that causes the scrotum to swell. It can occur from:

  • an injury within the scrotum
  • an infection of the testicles
  • a condition called epididymitis (inflammation of the epididymis, the tube that carries sperm from the testicles within the scrotum)

A hydrocele may resolve on its own without treatment. However, if the swelling becomes so severe that it causes pain or threatens the health of the testicles or other structures in the scrotum, surgery may be needed to drain the excess fluid.

Varicocele

A varicocele is an inflammation of blood vessels within the scrotum. It may be harmless, but can also reduce sperm production and the quality of your sperm.

A varicocele may be mild and cause no symptoms or complications, but if there’s pain or issues with infertility, surgery may be needed to treat the affected blood vessels.

Spermatocele

A spermatocele is the formation of a fluid-filled cyst in the epididymis, the coiled tube behind each testicle. A small cyst may be harmless and cause no symptoms. A larger cyst can cause pain and swelling within the scrotum. Surgery can remove the cyst.

Other causes

Other causes of scrotal swelling may include:

If you suspect one of these conditions is causing your scrotal swelling, see a doctor for diagnosis and treatment.

For men ages 40 and older, regular urologist visits are advised to check on your prostate.

It’s still a good idea to have regular doctor visits if you’re younger than 40. This is because testicular cancer occurs most often in men ages 20 to 34.

Also practice regular self-checks of your testicles to discover lumps or other changes to your testicles early. A self-check is simple and takes only a few minutes. Consider doing a check during or right after a warm shower. This will make it easier to do a more comprehensive check all around the testes.

Here’s how to do a self-check:

  • Stand in front of a mirror and look for any changes, such as swelling around one or both testicles.
  • Place your thumb and forefinger on either side of one testicle, and gently roll it back and forth, feeling for any lumps or irregularities. Do the same with the other testicle.
  • Feel for the epididymis, the cordlike structure in the back of the scrotum. Check for any changes there.

Do a self-check monthly. Let your urologist or primary care physician know promptly if you notice any changes.

It can be worrisome to have your body changing beyond what’s considered “normal” or average. This includes the testicles.

Generally, unless you have other symptoms like pain, having larger than average testicles shouldn’t be a cause of worry.

If the size change occurs after your testicles should’ve stopped growing, see your doctor. Regardless of when you became aware that your testicles seem too large, talking with your doctor will give you peace of mind.

It may also lead to a diagnosis of a condition that’s mostly likely treatable without many complications, like affecting your fertility.