Testicles come in many different shapes and sizes. It is also common for one testicle to be slightly larger than the other and for one testicle to hang lower. As with every other body part, testicle size varies from person to person, often with little or no effect on health.

The testicles produce the primary male sex hormone testosterone, as well as sperm. Testicle is an oval-shaped, sperm-producing organ within your scrotum. The average length of a testicle is between 4.5 to 5.1 centimeters (about 1.8 to 2 inches). Testicles that are less than 3.5 centimeters (about 1.4 inches) long are considered small. Most men have two testicles, also known as testes. It’s common for one of a man’s testicles to be a different size than the other testicle. Testicles reside in the scrotum, attached at each end to the spermatic cord.

A male’s testicle is about 1 cubic centimeter at birth and stays around that size until the testicles start growing about age 8. Then they grow steadily, reaching their adult size some time during puberty. It’s also during puberty that hair starts to grow on the scrotum and around the genitals.

Your testicles have two main jobs :

• Producing sperm for reproduction

• Secreting the male hormone testosterone, which is important in the development of male physical characteristics and sex drive

Since sperm is produced in your testicles, you may produce less sperm than average if you have smaller testicles. About 80 percent of a testicle’s volume is comprised of the seminiferous tubules, the tube-like structures that create sperm cells.

If you’re trying to father a child and you and your partner have been unsuccessful, you should consider seeing a fertility specialist. Your testosterone levels and sperm count can be measured to determine if they are related to your fertility troubles.

As you age, testosterone production tends to drop as your testicles start to get smaller. This is known as testicular atrophy. The change is often gradual and may not be especially noticeable. When it occurs naturally, there is no health threat. Lower testosterone levels can lead to a reduced libido and less muscle mass, but these tend to be natural parts of aging.

When the testicles are smaller than average, but there is no underlying medical condition, there are typically no side effects.

Medical conditions that cause small testicles can also produce other signs and symptoms. For example, a varicocele can cause pain and swelling in the scrotum.

Testicular atrophy can affect sexual and reproductive health in several ways. People may experience:

• pain in the testicles

• decreased fertility

• low libido

• sexual problems, such as erectile dysfunction

It’s important to discuss your concerns about your testicle size with your doctor. Your doctor can determine if your testicle size is a sign of an underlying health condition. It may be that your testicle size has nothing to do with erectile function or affects your sexual health in any way.

It is important to schedule an appointment with a healthcare professional if :

• pain, shrinking or swelling occurs in one or both testicles

• a partner does not become pregnant after a year or more of trying

• a lump appears in the scrotum

• unusual breast growth occurs

• there are symptoms of low testosterone, such as erectile problems or low energy

• other accompanying symptoms arise, such as lower back pain, shortness of breath, abdominal pain, a cough, confusion, or headaches

Having small testicles does not necessarily mean that a person has a health issue. However, a sudden change in the size or shape of the testicles could indicate a problem.