6 Common Causes of Small Testicles

The shape and size of the testicles varies from individual to individual. Another thing that is quite common is for one testicle to be smaller than the other. Now the question arises how much variability is normal when it comes to one testicle being shorter than the other. There are various ways to measure testicles. However, the most preferred measurement is of the volume and the size. On sheer volume, a normal testicle would measure around 20 cubic centimeters.[1]

With regard to the size, the measurement is taken from top to bottom. On average the size of the testicle should be anywhere between 4.5 to 5 cm. Anyone who has penis below this size may tend to worry a little bit but if there are no accompanying symptoms then it should not be something to be worried about.[1]

A major misconception among many males begins when they start comparing the size of their testicles with others. Instead, what they should look at is whether the size of their testicles have decreased over a period of time, as this may be a sign of an underlying problem. Read below to know the 6 common causes for small testicles.[1]

6 Common Causes of Small Testicles

  1. Low Testosterone Levels: This is believed to be one of the causes of a small testicle. A study conducted in 2017 showed that most of the participants with small testicles had low testosterone levels. However, there are many people that have normal testicular size but still have low levels of the sex hormone. Thus it is important to have knowledge of other symptoms and not just the size of the testicles for testosterone to be low.[1] A person with low testosterone levels will have a low sex drive. He will also have problems with achieving and maintaining erection. The individual will be irritable and will have frequent mood swings. Depression is yet another symptom that may be caused due to low testosterone levels.[1]
  2. Varicocele: This is a condition that is caused due to enlargement of the veins within the scrotum. Varicocele in many cases is asymptomatic in many people but some may experience pain and swelling around the genital area. Varicocele at times is also known to cause fertility problems in males. A study suggests that approximately 40% of males with infertility have varicocele but there is no concrete evidence as of yet as this being the primary cause.[1] People with varicocele will observe that one of their testicles becomes abnormally smaller than the other with pain and discomfort starting from deep within the scrotum. This condition can be treated surgically and in majority of the cases the testicles return back to their normal size after surgery.[1]
  3. Congenital Disorders: There are certain disorders that are present since birth which also cause one testicle to be smaller than the other. These congenital disorders are rare and include Klinefelter Syndrome in which the affected male has two X chromosome instead of one which is the norm. People with this condition also tend to have abnormally low testosterone levels and this is the reason why maximum males with Klinefelter Syndrome tend to be infertile. This condition also affects the brain and motor development during the childhood years.[1] Children with Klinefelter Syndrome tend to find tasks difficult to learn and have poor coordination skills. Some people may not even know they have Klinefelter Syndrome while in some cases a diagnosis is made very early in childhood.[1]
  4. Testicular Atrophy: This is a condition characterized by shrinkage of the testicles. This in majority of the cases is caused due to surgical procedure to treat inguinal hernia even though the chances of this complication are quite rare. However, the risk increases if an individual has repeated surgeries for this condition.[1] Testicular Atrophy can also be caused due to natural process of aging and sexually transmitted diseases. Some people with alcohol-related cirrhosis also get this condition.[1]
  5. Infertility: This is one of the rarer causes of one testicle being smaller than the other. There is very little data available connecting testicular size with infertility. A study done way back in the late 80s suggested that in about 1000 participants there were 700 who had normal testicular size. The other had some degree of decrease in the testicular size and volume.[1] Additionally, the sperm count and movement also got affected with the testicular size. Males with lower testicular volume had significantly low sperm count. Since more than 50% of people who participated in the study had normal testicular size a direct link could not be established.[1]
  6. Testicular Cancer: Testicular torsion is a condition which significantly shrinks the size of the testicles. However, it also increases the risk for testicular cancer. If this is the case, then there will be a sudden drop in the size of the testicles. The symptoms of testicular cancer are quite similar to that of other types of cancer and thus it is important to observe for other symptoms like a lump on the testicles or abnormal fluid discharge from the scrotum. In some cases, there is also abnormal enlargement of the testicles. The testicles also feel heavy.[1]

Apart from the symptoms, it is also important to have knowledge about the risk factors for testicular cancer. These include a known diagnosis of undescended testicles. People with a family history of testicular cancer are more at risk for developing this condition that those who do not have a family history, especially in people who have a first degree relative with testicular cancer. People with a known diagnosis of HIV are also at risk for developing testicular cancer.[1]

People with a known diagnosis of testicular cancer in one testicle are at an increased risk for developing cancer in the other testicle as well. Studies suggest that whites have at least 4 times higher risk of developing testicular cancer than African-Americans or Asian Americans. Age also plays a factor in that most cases of testicular cancer are diagnosed between the ages of 20 and 35.[1]

In conclusion, the size of the testicle is quite variable and is different from person to person. It is also quite common to see one testicle being a bit smaller than the other. In most cases it is a benign condition; however, if this occurs gradually over a specific period of time or the size of the testicle suddenly shrinks then it is a sign of an underlying problem.[1]

There are many causes for a testicle being small. Among the most common cause is varicocele and testicular atrophy. Testicular cancer is also one of the causes of the testicle becoming suddenly small. All these cases need to be investigated thoroughly, especially if an individual has a risk for developing testicular cancer. This is necessary as an early diagnosis is the key to an overall good prognosis of the patient.[1]


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