In males, fertility refers to the ability to make healthy sperm that can fertilize an egg to cause pregnancy. Infertility happens when there is a problem with how sperm are made, stored, or released.
Infertility and other fertility problems can be side effects of certain chemotherapy medicines, radiation therapy, or surgery. This does not mean that everyone who has these treatments will have fertility problems. Each person’s risk is different. Many people who have treatment-related fertility problems are still able to have children later in life, either naturally or with medical help.
Fertility preservation options are ways to help protect fertility to give a better chance of fathering a child in the future.
Before treatment starts, talk with your care team about possible effects on fertility and options to protect fertility.
Parts of the male reproductive system
Puberty is the stage in life when a boy’s body goes through physical and hormonal changes that prepare him for adulthood. This usually occurs between ages 9 and 16. During puberty, the brain signals the testicles to make testosterone, a hormone that causes changes such as facial and body hair growth, a deeper voice, and the start of sperm production.
Sperm are made in the testicles and then move to the epididymis, a coiled tube where they are stored and continue to mature. During sexual activity, sperm travel through the vas deferens, a tube that carries them to the urethra, which runs through the penis. Along the way, sperm mix with seminal fluid to create semen. During orgasm, semen is released through the urethra and out of the penis. This is called ejaculation.
Chemotherapy, radiation, surgery, or illness can affect the reproductive organs or brain. This can lead to:
Some changes to the body may be temporary. Other changes could be long-term or permanent.
Risk factors for fertility problems include:
Effects on fertility depend on:
Some chemotherapy medicines have a higher risk of causing fertility problems. These include:
| Alkylating Drugs |
Heavy Metal Drugs |
|---|---|
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| Non-classical alkylators |
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A health care provider can diagnose fertility problems after puberty. Screening may start with a physical exam and medical history. Tests may be used to measure sperm or hormones.
Semen is the bodily fluid that contains sperm. A semen analysis, also called a sperm count, measures the quantity and quality of sperm. Results of the analysis include:
Healthy males make sperm their entire lives. If sperm are present after chemotherapy or radiation is complete, the body is likely to continue to make sperm. If no sperm are found, it may mean that your body cannot make sperm.
Blood tests are used to measure the level of certain hormones, such as:
Your care team can explain test results and let you know if you need other tests.
Fertility treatments and male fertility preservation options depend on many factors, including age and past and future treatments. Not all options are safe and effective for all patients.
Some fertility preservation procedures may not be covered by health insurance. They may be an out-of-pocket expense. Ask your care team about financial assistance programs or grants for fertility preservation.
Fertility treatment options depend on whether puberty has started. Talk to your care team to understand the options, costs, and risks.
Some people think they cannot have children and may skip birth control. But pregnancy can happen, even with low sperm counts. If you are sexually active and not planning a family, use birth control. Use condoms to help prevent sexually transmitted infections (STIs).
Talk to your care team about the risk of fertility problems before starting treatment, even if your care team does not bring it up. These questions can help you to plan ahead and find support:
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Reviewed: April 2026
Fertility problems (infertility) can be a side effect of illness or treatments. Learn about male fertility preservation options and how to talk to your doctor.
Fertility problems (infertility) can be a side effect of illness or treatments. Learn about female fertility preservation options and how to talk to your doctor.
Childhood cancer survivors may worry about fertility and their ability to have children. Learn how cancer treatments might affect reproductive health.