What Are Testicles? Understanding What They Are and What They Do
Testicles are vital organs in the male reproductive system responsible for producing sperm and sex hormones, including testosterone. Testosterone helps drive many of the characteristics that are associated with masculinity, such as facial hair, a deeper voice, and muscle growth, and sperm are necessary for sexual reproduction.
Testicles may also be referred to as testes or male gonads. Of course, the organs also have a variety of casual nicknames, such as “balls” and “nuts.”
Males (and people assigned male at birth) generally have two testicles, which are oval-shaped and located in the scrotum. The scrotum is a pouch of skin that hangs outside the body, behind the penis and between the legs. The testicles are located outside the rest of the body in order to maintain a cooler temperature, which is better for sperm production.
The primary role of testicles is to make sperm and testosterone. Before puberty, male children only secrete a very small amount of testosterone, and do not produce any sperm. But as their bodies change, the testicles and scrotum grow to begin making these two substances.
Sperm Production
Sperm is the male reproductive cell. These microscopic cells carry a mixture of their creator’s DNA. With whiplike tails, they are designed to find and fertilize an egg, the female reproductive cell, creating a new embryo that can grow into a new child.
Within the testicle, immature sperm travel through the epididymis, a six-meter-long coiled up tube; during the journey they mature and become mobile. During ejaculation, millions of sperm are pushed through the vas deferens, combining with liquids secreted from several glands to form semen. Semen is finally pushed out of the penis through the urethra.
Unlike women, men are capable of reproduction at advanced ages, but aging does bring changes to both the testicles and to the sperm that they produce. The testicles may shrink, and individual parts within the testicles can become less flexible and less productive. At older ages, men may be more likely to pass on genetic mutations to their children, occasionally resulting in conditions such as skeletal dysplasias or dwarfism. A man’s fertility — his likelihood of impregnating a partner — will also decline.
Testosterone Production
The hormone testosterone is responsible for increased muscle mass, facial and body hair growth, and deepening of the voice during puberty. The hormone also influences libido, bone density, and overall energy levels, contributing to emotional well-being and physical health.
Testosterone production naturally begins to decline around the age of 30, and continues to slowly decline throughout the rest of a man’s life. Your testicles may shrink as you age.
Though gradual testosterone declines are natural, sudden decline is a cause for concern, and can lead to a wide variety of symptoms and complications. Maintaining adequate testosterone levels is important for overall vitality in men.
Like any part of the body, testicles can be affected by disease, injury, or infection. Here are some of the most common conditions and complications of the testicles.
Hydrocele
A hydrocele is a type of swelling in the scrotum that happens when fluid collects in the thin sac that surrounds a testicle. It often occurs in newborns, and it goes away without treatment by age one. Older children and adults can get hydrocele as the result of an injury to the scrotum or other health issues. It doesn’t always require treatment, but people should see a healthcare provider if the scrotum looks swollen.
Varicocele
Varicoceles are enlarged veins within the scrotum that can contribute to infertility. Symptoms are usually mild, but some people notice dull pain, swelling or shrinking in the testicles, or a small lump above the affected testicle. Varicoceles often resolve on their own, and can sometimes be treated with ice or even a different style of underwear. But in severe cases marked by significant pain or infertility, surgery may be necessary.
Testicular Torsion
Testicular torsion is a painful condition where the testicle twists, cutting off its blood supply. It can be caused by an injury, but most cases happen in people who have “bell clapper” testicles, which allow the testicles to move freely in the scrotum.
Symptoms include sudden, severe pain and swelling. This condition is a medical emergency; if not treated within a few hours, it can lead to permanent damage or loss of the testicle.
Low Testosterone (Hypogonadism)
Low testosterone, or hypogonadism, is a condition where the body isn’t making enough testosterone. Males can be born with low testosterone, or it can develop later in life. Many different health conditions can lead to low testosterone production, including obesity, type 2 diabetes, heart failure, and autoimmune diseases.
In children, low testosterone causes delayed puberty and lack of secondary sexual characteristics, such as facial hair or a deeper voice.
In adults, low testosterone can cause both sexual symptoms, such as erectile dysfunction, infertility, or enlarged breasts, and nonsexual symptoms, such as fatigue and depression. In some cases, low testosterone is managed with hormone replacement therapy, but clinicians may also advise lifestyle changes such as exercise and weight loss.
Testicle Infections
Infections can cause pain, swelling, and tenderness in the testicular area, as well as fever and general illness.
Epididymitis is inflammation of the epididymis, the coiled tube at the back of the testicle, commonly caused by intestinal bacteria or the sexually transmitted diseases chlamydia or gonorrhea.
Orchitis is a viral infection that spreads to the testicle through the bloodstream.
The pain of an infected testicle can be bad enough to make walking difficult or impossible. You should call a doctor immediately if you suspect a testicular infection. Treatment with antibiotics is often fast and successful.
Because the testicles are on the outside of the body, they are more vulnerable to blunt force and penetrating injuries. Injuries to the testicles can include dislocation, which is when something forces the testicle out of position, or degloving, which is when an accident removes the scrotum covering the testicles.
Symptoms typically involve intense pain, swelling, and bruising. It’s important to seek medical care immediately for this type of injury because it can lead to complications, such as loss of the testicle.
Testicular Cancer
Testicular cancer is the most common form of cancer among young males.
Cancer of the testicles usually takes the form of out-of-control growth of the cells that produce sperm. It often presents as a bump or lump in the testicle, and may cause a dull ache in the lower belly, groin, testicle, or scrotum.
Treatment usually involves the surgical removal of the testicle. If the cancer has spread, surgery might be followed by chemotherapy or radiation. Testicular cancer is highly treatable; only a tiny minority of men with the condition will die from it.
Male Infertility
Conditions such as varicocele, hormonal imbalances, and infections can all cause infertility — the inability to conceive a child. A man might become infertile for a number of reasons, including low sperm production, abnormal sperm function, or blockages that prevent the delivery of sperm.
Infertility may have no other symptoms, but can lead to profound disappointment and emotional stress. Treatment options vary, ranging from lifestyle changes and medications to assisted reproductive technologies such as IVF, depending on the underlying cause.
It is possible to catch testicular cancer and other issues early by performing regular self-examination. Some experts recommend men should examine their testicles each month between puberty and the age of 40.
Here’s what to look for: Look and feel for any hard lumps or nodules (smooth rounded masses) or any change in the size, shape, or consistency of your testicles. If you examine your testicles regularly, you’ll know what’s normal and what’s different. If you feel any lumps, changes in size or shape, unusual swelling, or bloody semen, let your healthcare provider know right away.
Testicles are vital organs that produce sperm and testosterone, which are essential for fertility and help create defining male characteristics like facial hair and a deeper voice. While sperm and testosterone production naturally declines as men age, more significant issues can also affect the testicles, including cancer and infertility. Regular self-exams and knowing what’s normal for you can help catch any potential issues early.
