At What Age Should You Get Genetic Testing for Cancer Risk?

By Amanda Shrewsbury, MS, CGC

One of the most common questions people ask about genetic testing is "when is the right age to test?" — whether it's about themselves, their children, or grandchildren. The honest answer is nuanced. There is no single right age for genetic testing, but there is a right time depending on personal and family history, or the particular genetic mutation involved.

The reason there is no universal number is that genetic testing is most useful when its results would actually change something: when they would inform a screening decision, a prevention option, a reproductive choice, or a family member's care. The right time to test is the time when that information becomes actionable for you. For some people that is their twenties; for others it is later in life; and for a small number of families with specific syndromes, it may even be childhood.

This post walks through how to think about timing across the stages of life, including the question many parents ask about testing children, and the reassuring answer for older adults who wonder whether they have missed their window.

Is there a single right age to get genetic testing?

No. There is no single age at which everyone should be tested. For most hereditary cancer syndromes, testing is considered in adulthood, and the right timing within adulthood depends on your family history and the specific genes that may be involved.

The guiding principle is straightforward: the goal is to have results in hand before the age when screening or risk-reducing decisions would begin. If a result would lead to enhanced screening starting at age 25, then testing in the early twenties makes sense. If a family history suggests risk that would change care earlier, the timeline moves up accordingly. The result itself does not change with age, because the variant has been present since birth. What changes is whether you are at a point where knowing would shape your care.

Why most hereditary cancer testing starts in adulthood

Most hereditary cancer syndromes are adult-onset, meaning the associated cancers typically occur in adulthood. Because of this, testing is generally timed to adulthood, when enhanced screening and risk-reducing options become relevant.

This is not an arbitrary cutoff. Genetic testing is most appropriate when the result would change medical management, and for adult-onset conditions, that management (such as earlier mammograms, breast MRI, colonoscopy, or risk-reducing surgery) begins in adulthood. Testing earlier, during childhood, generally would not change anything about a child's medical care, which is the central reason it is usually deferred.

Should children be tested for hereditary cancer genes?

This is one of the most common and most emotionally charged questions parents ask, and the answer reflects a careful, well-established consensus in the genetics field.

For most hereditary cancer syndromes, which are adult-onset, the recommendation is to defer testing until the child reaches adulthood and can decide for themselves. This is the position held by major professional organizations including the American Society of Human Genetics and a joint statement from the American Academy of Pediatrics and the American College of Medical Genetics and Genomics (Botkin et al., 2015; Ross et al., 2013). The reasoning has two parts. First, testing a child for an adult-onset condition would not change their medical care during childhood. Second, deferring preserves the child's future right to decide for themselves, as an adult, whether and when they want this information.

There is an important exception. A small number of hereditary cancer syndromes have childhood-onset components, where screening or intervention genuinely begins in childhood. The clearest example is familial adenomatous polyposis (FAP), caused by variants in the APC gene, where screening for colorectal polyps begins in childhood or early adolescence. Other examples include certain forms of multiple endocrine neoplasia and some childhood-onset cancer predisposition syndromes. For these conditions, testing a child is appropriate, because the result directly affects the care the child receives now.

The distinguishing question is always the same: would testing change the child's medical management during childhood? If yes, testing may be appropriate. If no, the recommendation is generally to wait. These decisions are deeply individual, and they are best made with a genetic counselor and a child's pediatric care team, who can weigh the specific syndrome, the family situation, and the child's interests together.

Testing in your 20s and 30s

For many people, the twenties and thirties are a natural window for testing. This is often when results become actionable for the first time.

For people who carry a BRCA1 or BRCA2 variant, for example, NCCN guidelines recommend annual breast MRI beginning at age 25, with mammography added at age 30 (NCCN, 2025). Having testing done before those ages means a person can begin the recommended screening on schedule rather than discovering their risk after the window has already opened. The twenties and thirties are also when many people begin thinking about reproductive choices, and a known result can inform that planning, which is a conversation a genetic counselor can walk through in detail.

When family history should move up your timeline

Family history is often what determines the right age to test, and a strong family history generally moves the timeline earlier.

A common principle in cancer screening is to begin surveillance about 10 years before the earliest cancer diagnosis in the family. For example, NCCN recommends that a person with a first-degree relative who had colorectal cancer begin colonoscopy at age 40, or 10 years before the earliest diagnosis in the family, whichever comes first (NCCN, 2025). If someone's parent was diagnosed with colorectal cancer at 45, it is recommended that they begin colonoscopy screening at age 35. Because testing ideally precedes the start of screening, a significant family history is often a reason to test earlier rather than later. This is one of the clearest examples of why mapping out the family history with a genetic counselor matters: the youngest diagnosis in the family often sets the clock.

Testing before having children

Some people choose to pursue genetic testing during their family-planning years, before or between pregnancies. A known result can open up reproductive options to discuss with a genetic counselor, and it gives people time to consider those options without the time pressure of an active pregnancy. This is a personal decision, and there is no obligation to test before having children, but for those who want the information at that stage, it is a valid and common reason to test in early adulthood.

Is it ever too late to get genetic testing?

No. There is no upper age limit for genetic testing, and it is never too late for testing to be valuable.

For an older adult, testing can still inform their own remaining screening and risk-reducing decisions. Just as importantly, a result can provide critical information for the whole family. When an older adult tests positive for a hereditary cancer variant, that result often opens the door to cascade testing, allowing children, grandchildren, and other relatives to learn whether they share the variant and to act on that knowledge during their own prime prevention years. In this way, testing later in life can be one of the most generous things a person does for the generations after them. Our post on cascade testing explains how that process works.

How age interacts with what testing can tell you

It is worth understanding a subtle but reassuring point: the result of a genetic test does not change with age. A pathogenic variant has been present since birth, and testing simply reveals whether it is there. A test done at 25 and a test done at 65 would return the same result for the same person.

What changes with age is not the result but what you do with it, and how urgently. Knowing at 25 gives a person decades to act on the information. Knowing at 65 still allows for meaningful screening and prevention decisions, and it still benefits the family. The information is valuable at any age; the age simply shapes how it is used.

How to decide the right time for you

There is also a human side to timing that deserves to be named. Beyond the clinical considerations, the right time to test is also a time when you feel prepared to receive the information. Some people want to know as soon as possible. Others need time to feel ready. Both are valid, and a genetic counselor can help you think through not only the clinical timing but also your own readiness.

When you are deciding, the practical questions are: Would a result change my screening or prevention options now or soon? Does my family history point toward starting screening at a particular age? Would testing benefit my relatives? And do I feel ready to learn this information? A genetic counselor can help you weigh all of these together.

A few resources from our blog that may help:

Finding your right moment

The right age for genetic testing is less about a number and more about a moment. The moment at which you or your family members can take actionable steps for prevention and early detection, and the moment that you feel prepared to learn the information. A genetic counselor can help you find that right moment.

---

Talk with a ClearPath Genetic Counselor

If you are wondering whether now is the right time for genetic testing, for yourself or someone in your family, we are here to help you think it through.

Have a Question? Text or call us at (720) 799-0730 or email us at hello@clearpathgenetics.com.

---

References

Botkin, J. R., Belmont, J. W., Berg, J. S., Berkman, B. E., Bombard, Y., Holm, I. A., Levy, H. P., Ormond, K. E., Saal, H. M., Spinner, N. B., Wilfond, B. S., & McInerney, J. D. (2015). Points to consider: Ethical, legal, and psychosocial implications of genetic testing in children and adolescents. American Journal of Human Genetics, 97(1), 6–21.

National Comprehensive Cancer Network. (2025). NCCN clinical practice guidelines in oncology: Genetic/familial high-risk assessment — Breast, ovarian, and pancreatic; and Colorectal cancer screening. https://www.nccn.org/

Ross, L. F., Saal, H. M., David, K. L., & Anderson, R. R.; American Academy of Pediatrics; American College of Medical Genetics and Genomics. (2013). Technical report: Ethical and policy issues in genetic testing and screening of children. Genetics in Medicine, 15(3), 234–245.

---

This blog post is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the advice of your physician, genetic counselor, or other qualified healthcare provider with any questions you may have regarding a medical condition or your individual health needs.