Breast Cancer and Genetics: How to Assess Your Family Risk

Breast cancer can be hereditary, especially if women in your family have had it. If that’s the case, it’s natural to wonder whether you may have inherited certain gene mutations. But how can you assess your genetic risk?

Breast cancer is a serious disease that affects one in eight women. If you are in your forties, chances are that an important woman in your life—your mother, aunt, grandmother, or close friend—has already faced this diagnosis. But what if you are genetically related to her? The fear of carrying mutations such as BRCA genes, which are linked to breast and ovarian cancer, is completely understandable.
Fortunately, only a relatively small percentage of women—about 5 to 7 percent—carry genetic predispositions for this disease. This means that having a relative with cancer does not automatically mean you will develop it. Still, it’s worth evaluating your genetic risk, as hereditary breast cancer tends to be more aggressive. So, what should you do?

How to Check for Genetic Risk of Breast Cancer

Your genetic risk increases with the number of affected relatives and how closely related they are to you—but those aren’t the only factors. You should speak with a doctor if your mother, sister, or aunt has had breast cancer, or if there are two or more cases in your family. The first step is to consult a genetic specialist or oncologist and create a detailed family medical history.

Questions to Ask Your Mother—and What Every Daughter Should Know

We’ve already established that not every case of breast cancer in a family points to a genetic cause. But if you’re concerned, it’s time to gather key information:

Which family members, on both sides, have had breast cancer?
If one or more close relatives have been diagnosed, your risk may be higher. However, not all relatives carry the same weight. First-degree relatives—your mother, sister, and daughter—are the most important, as you share about 50% of your genes. If one of them has had breast cancer, your risk increases; if more than one, it increases further.
Second-degree relatives include grandmothers, aunts, and cousins. Both your mother’s and your father’s side are equally important, since genetic mutations can be inherited from either parent. In other words, an aunt on your father’s side matters just as much as one on your mother’s side.

Has anyone had breast cancer in both breasts?
Bilateral breast cancer can indicate a stronger genetic component. When cancer appears in both breasts, the likelihood of a hereditary predisposition is higher. This may prompt doctors to recommend closer monitoring.

Has anyone in your family had ovarian cancer?
Certain genetic mutations increase the risk of multiple cancers, including breast and ovarian cancer. If different types of cancer appear within the same family, it may suggest a shared genetic cause. This pattern is important for assessing overall risk.

How old were your relatives when they were diagnosed?
Breast cancer diagnosed at a younger age (before 50) is more likely to have a genetic basis. The earlier the diagnosis, the higher the likelihood of hereditary predisposition. This helps doctors evaluate how significant the risk may be.

Have any male relatives had breast or prostate cancer?
Breast cancer in men is rare and often linked to genetic factors. Certain mutations can also increase the risk of prostate cancer. If these cases occur in your family, they may strongly suggest a genetic predisposition.

Do you have Jewish ancestry?
People of Ashkenazi Jewish descent have a higher frequency of specific genetic mutations associated with breast cancer. As a result, the statistical risk is higher in this population. This information helps doctors assess individual risk more accurately.

What If You Have a Genetic Risk?

Having a genetic predisposition to breast cancer does not mean you will definitely develop the disease—it means your risk is higher than average. The first step is to talk to your doctor, who can evaluate your family history and recommend appropriate follow-up.
This usually includes more frequent screenings, such as ultrasound, mammography, or MRI, depending on your age and level of risk. You may also choose to undergo testing for BRCA gene mutations to better understand your situation and remove uncertainty.
The key is knowledge: understanding your risk allows you to take timely action, stay proactive about your health, and make informed decisions.