The causes of testicular cancer are mostly unknown, but certain factors raise your risk
Most men who get testicular cancer have no family history of it and no clear reason why it happened. Doctors cannot yet predict who will develop it or prevent it through lifestyle changes. What researchers do know is that testicular cancer starts when cells in the testicle begin to grow abnormally, and a handful of conditions or characteristics make this more likely—though having a risk factor does not mean you will get cancer.
The strongest known risk factor is a history of undescended testicles, either in childhood or at birth. Men who had testicular cancer in one testicle face a higher chance of developing it in the other. Age also matters: testicular cancer most often appears in men between 20 and 40, though it can occur at any age. Beyond these, the picture becomes less clear, and much remains unknown about why the disease develops.
Key Takeaways
- Undescended testicles at birth or in early childhood carry the highest known risk for testicular cancer, even if the testicle was corrected surgically.
- A personal history of testicular cancer in one testicle increases the risk of cancer in the other testicle over your lifetime.
- Testicular cancer occurs most often in men aged 20 to 40, but can develop at any age.
- Family history of testicular cancer raises risk slightly, though most men with testicular cancer have no family connection to the disease.
- Most lifestyle factors—diet, exercise, sexual history, or occupation—have not been proven to cause or prevent testicular cancer.
Undescended testicles as the strongest risk factor
An undescended testicle, called cryptorchidism, is the most established risk factor for testicular cancer. Normally, testicles descend from the abdomen into the scrotum before or shortly after birth. When one or both testicles remain in the abdomen or groin instead, the risk of cancer rises in that testicle—even if it is brought down surgically later in childhood.
The increased risk persists whether the testicle was corrected early or late, and whether it was corrected at all. Doctors do not fully understand why undescended testicles are more prone to cancer, but the abnormal position and temperature may play a role. If you had an undescended testicle as a child, you should know your personal risk is higher and discuss screening or self-examination with your doctor.
Personal history of testicular cancer in the other testicle
Men who have had testicular cancer once face a 3 to 5 percent chance of developing cancer in the remaining testicle during their lifetime. This is much higher than the risk in the general population. The reason is not fully understood—it may reflect an underlying condition that affects both testicles, or it may be coincidence.
Because of this risk, men who have survived testicular cancer are usually advised to perform regular self-examinations and see their doctor for periodic checks. Some doctors recommend ultrasound screening of the remaining testicle at intervals, though there is no universal standard for how often. Talk with your oncologist or primary care doctor about what monitoring makes sense for you.
Age and testicular cancer risk
Testicular cancer is the most common cancer in men aged 20 to 40, with peak incidence in the 30s. It can occur in teenagers and in men over 50, but this is less common. The reason testicular cancer clusters in young adulthood is not known.
Because the disease strikes men in their working and family-building years, it often has major life impact. Younger men may not expect a cancer diagnosis and might delay seeking care if they notice a lump or change. Knowing that testicular cancer is most common in this age group can prompt faster attention to symptoms.
Family history and genetic factors
Men whose father or brother had testicular cancer face a higher risk than men with no family history. The increased risk is real but modest—roughly 8 to 10 times higher than average, though the absolute risk is still low. No single gene has been identified as causing testicular cancer, and most cases are not inherited.
Certain genetic syndromes, such as Klinefelter syndrome (an extra X chromosome), are associated with higher testicular cancer risk. Down syndrome and some other chromosomal conditions also raise risk. If you have a family history of testicular cancer or a known genetic condition, discuss your personal risk with your doctor.
Factors that have not been proven to cause testicular cancer
Researchers have studied many potential causes—trauma or injury to the testicles, sexually transmitted infections, vasectomy, marijuana use, occupational exposures, and diet—without finding consistent evidence that any of these cause testicular cancer. While some studies have suggested links, others have not confirmed them, and no clear causal relationship has been established.
This does not mean these factors are safe or unsafe in general; it means they are not currently understood to be causes of testicular cancer specifically. Lifestyle changes cannot prevent testicular cancer, and there is no known way to reduce your risk if you do not have one of the established risk factors. The focus remains on early detection through self-examination and prompt medical evaluation of any changes.
What happens after a testicular cancer diagnosis
If testicular cancer is found, treatment depends on the type, stage, and spread of the disease. Options include surgery to remove the affected testicle, radiation, chemotherapy, or a combination. Survival rates are high, especially when cancer is caught early, and many men go on to live full lives after treatment.
Understanding the cause of your cancer does not change the treatment plan, but it may help you understand your ongoing risk and what monitoring you need. Your oncology team will discuss your specific situation, prognosis, and follow-up care with you in detail.
Frequently Asked Questions
If I had an undescended testicle that was fixed in childhood, will I definitely get testicular cancer?
No. Having an undescended testicle raises your risk, but most men with this history never develop cancer. You should be aware of your higher risk and perform regular self-examinations, but a corrected undescended testicle does not may provide cancer will develop.
Can testicular cancer be prevented?
There is no known way to prevent testicular cancer. Lifestyle changes, diet, or exercise have not been shown to reduce risk. The best approach is awareness of your personal risk factors and prompt attention to any lumps, swelling, or changes in your testicles.
Does trauma or injury to the testicles cause cancer?
Injury to the testicles has not been proven to cause testicular cancer. However, an injury may draw attention to a lump or change that was already present, leading to a diagnosis. If you notice a change after an injury, see your doctor to have it checked.
Is testicular cancer hereditary?
Testicular cancer can run in families, but it is not strictly hereditary. Having a father or brother with testicular cancer raises your risk, but most men with testicular cancer have no family history. No single inherited gene has been identified as the cause.
What should I do if I have multiple risk factors?
If you have a personal or family history of testicular cancer, or if you had an undescended testicle, discuss your risk with your doctor. They may recommend regular self-examination, periodic clinical checks, or ultrasound screening to catch any changes early.