Is One Testicle Bigger Than the Other Normal?

Not only is it normal to have one testicle that is bigger than the other, it’s also common to have one that hangs a bit lower. However, asymmetrical testicles that develop suddenly and are accompanied by pain and other symptoms are cause for concern.

This article describes the anatomy of testicles and why they may differ in size. It also covers the various conditions that can adversely affect testicles, how to perform a testicular self-exam, and when it is time to see a healthcare provider.

Normal Testicle Characteristics

The characteristics of testicles can vary from one person to the next but generally have the following features:

• Adult testicles are roughly 2 to 3 inches long by 1 inch wide.
• Testicles may be different in size but will usually be of the same or similar shape.
• Each testicle will feel like a firm, smooth egg.
  
• Pain can occur if testicles are hit or roughly handled, but not when they are touched or examined.

Asymmetrical testicles are not uncommon. In most cases, they are not a problem. Testicles can be different sizes because the right testicle of a male fetus tends to develop first and more quickly than the left one during pregnancy.

Abnormal Testicle Characteristics

Having one testicle that is bigger than the other is not, in and of itself, a sign of a problem. Rather than focusing on that, be on the lookout for the following signs and symptoms, which can indicate an abnormal condition affecting the testicles:

• Changes in testicle size
  
• Changes in the shape of a testicle
• Pain, tenderness, or swelling
• A lump or growth on a testicle, with or without pain
• The sudden retraction of one testicle but not the other

If you experience any of these, see your healthcare provider.

Conditions That Can Cause Testicle Changes

There are some common conditions that can cause lumps, pain, or swelling of the testicles. These are usually not life-threatening but do require medical attention.

These conditions include:

• Hydroceles: This is the swelling of the scrotum (the sac of skin beneath the penis) due to the buildup of fluid. Hydrocele is common in newborns and usually disappears without treatment. In late life, it can develop due to inflammation or injury.
• Varicocele: This is the enlargement of the veins that transport blood from the testicles. A varicocele occurs when blood pools in the veins rather than circulating as it should.
• Orchitis: This is the inflammation of a testicle usually caused by an infection.
• Epididymitis: This is inflammation of the epididymis, a small coiled tube situated just behind each testicle that collects and stores sperm. This is usually caused by an infection.
• Inguinal hernia; This is when part of your intestines pushes through muscles in the groin and protrudes into the scrotum.
• Testicular trauma: This can occur during contact sports or being struck in the groin. Testicular injuries can lead to swelling, pain, bruising, and blood in the urine.
• Testicular cancer: Typically occurring between the ages of 15 to 45, testicular cancer can cause a heaviness in the scrotum accompanied by a painless lump, asymmetrical swelling, and hydroceles.
  
• Testicular torsion: This a medical emergency caused by the twisting of the spermatic cord, a bundle of nerves, ducts, and blood vessels that connect the testicles to the abdominal cavity.

Testicular Self-Examination

A testicular self-exam is a manual evaluation to check for lumps, pain, or other unusual change in your testicles. It is commonly used as a preventive tool for testicular cancer.

To do a testicular self-examination:

1. Shower or bathe to ensure the scrotum is relaxed and warm.
2. Stand in front of a mirror if it helps you get a better look.
3. Use the fingers and thumbs on both hands to gently roll the testicle, checking for lumps or any painful areas.
4. Feel along the underneath and back of the scrotum to locate the epididymis (it should feel like a bundle of tightly coiled tubes). 
5. Repeat on the other testicle.

Summary

Having one testicle that is always slightly larger than the other is entirely normal. However, swelling, pain, lumps, or sudden changes in the size or position of a testicle are not.

Doing monthly self-exams is a good way to watch for changes that could indicate a potentially serious medical problem, including testicular cancer. Also be sure to keep up with your routine physical examinations.

A Word From Verywell

It’s important to note that testicular cancer is rare. Although it’s vital to seek medical attention when you find a lump or any other abnormality, there is no need to panic. The symptoms are often the result of a less serious condition.

Even if cancer is the cause, early diagnosis almost invariably leads to better outcomes.