Men usually focus only on their penis and don't pay enough attention to their other male genitalia. The testicles, often referred to as their "balls", are located in the scrotum or ball sacks of the male. They are located outside of the body while inside the scrotum, because they require a temperature that is a bit lower than the normal male body temperature. In the testicles, testosterone is made and sperm cells are created. The sperm then leaves the testicles through the vas deferens in order to fertilize the egg in reproduction.

One Testicle Smaller Than the Other, Why?

If you are a normal man, your testicles are about the same size. However, one testicle which is smaller than the other is not considered abnormal. One testicle (left one) usually hangs lower than the other because of the way the blood supply enters the testicles. It can cause a man to feel as though one testicle is smaller than the other. Testicular size is not that important when it comes to male fertility or to male sexual function.

There are situations, however, where a testicle changes sizes obviously or develops bumps, soreness, or increased sensitivity at the same time. Then you should be concerned about it as some diseases including the following may cause the problem.

• Hydrocele. This results from having a collection of fluid developed near the testicle. It results in swelling of the scrotum and is more common in men who are older. A hydrocele can develop around just one testicle or around both testicles.
• Spermatic cyst. If you have one testicle smaller than the other, it can be from a benign cyst that begins to develop near the epididymis, located in the backside of the testicle.
• Epididymitis. This results from an infection of the epididymis, which is the collecting part of the testicles. When you have this type of infection, you can suffer from swelling, fever, and pain on the topside and backside of the testicle. The pain may be severe, and develops gradually over time.
• Orchitis. This involves having an inflamed testicle from the mumps virus or a bacterial infection. Common symptoms include pain, swelling of the testicle and a feeling of increased scrotal weight. Orchitis can be dangerous; it can damage the testicle permanently, causing a shrinking of the testicle and a loss of fertility.
• Testicular varicosities. This is a painless condition in which an area of the scrotum feels like a sack of worms. These aren't inherently dangerous, but they can cause infertility because they raise the temperature of the testicles.
• Testicular torsion. This is a serious condition in which the testicle twists on its cord, causing severe pain and a lack of circulation to the testicle. It is a serious emergency and needs to be fixed surgically as soon as possible. If it lasts longer than a couple of hours, it can do permanent damage to the testicle, resulting in removal of the testicle.
• Testicular cancer. Only about four out of every 100 testicular lumps are cancerous, so testicular cancer is not common. It is fortunately very curable if caught early enough. When you have testicular cancer, there is one testicle smaller than the other and one that is enlarged with a lump. It can be uncomfortable or painful.

If you have noticed one testicle is smaller than the other and other related symptoms, seek the advice of your doctor in order to have it evaluated. The doctor will tell you what is wrong with the testicle and will select the proper treatment for your problem.

Testicular Self-Exam

As there can be several different kinds of diseases resulting in one testicle being smaller than the other, you should be watching your testicles carefully. In order to do this, each man should check his testicles on a regular basis like once a month in order to know what the testicles feel like so that changes can be detected early enough. The testicular self-examination goes as follows:

1. Undress yourself and stand in front of a mirror. Look for possible swelling in the skin of the scrotum. One testicle smaller than the other slightly is completely normal.
2. With both of your hands, check each testicle separately. Put your fingers behind the scrotum and your thumb on the top of the scrotum. Gently roll the testicle between your thumb and fingers.
3. You will feel the epididymis on the top and back side of the testicle. It feels like a bunch of cords. The epididymis is about 1 inch long and is sensitive but not painful to handle. It is not a lump but a normal part of the testicle.
4. Check for any tender, painless, or hard lumps on the testicle. Lumps can be about the size of a pea or can be bigger than that.
5. Do both testicles as there can be problems with either one.

If you note any lump or swelling of the testicle, check with your doctor. Most of the time, the lumps are not cancerous. It is much more common to have nodules and cysts on the testicle but you should have every lump checked out.

You can also learn the process vividly by watching the video below: