First things first: use our family history worksheet to determine if you have a family history of cancer. If you don’t have a family history, you don’t need genetic testing.

But if you do have a family history, what branches of your family tree actually matter when considering genetic testing?

To answer this question, genetic counselors like to look at three generations; this is because first degree relatives (parents, siblings and children), second degree relatives (aunts, uncles, grandparents, grandchildren) and third degree relatives (great aunts and uncles, first cousins) all “count” when trying to decide if you should consider genetic testing.

If your family member who was/is affected with cancer is living, that person would be the best person to test. If that person does not have a genetic mutation, the rest of the family would not need testing.

If your family member who was affected with cancer is deceased, you may not be the best person to test. For example, if your paternal aunt had cancer and is deceased, then a genetic counselor would want to test your father first to see if he inherited a genetic mutation from his parents; if he did not inherit a genetic mutation in any of the genes that can predispose you to cancer, there would be no way he could pass that mutation on to you.

It’s a common myth that a woman is “safe” from cancer if the women on her father’s side of the family had cancer, but not her mom’s. Men can still inherit genetic mutations that would predispose a woman to a female cancer, but of course they wouldn’t have symptoms because they don’t have female organs (ovaries, fallopian tubes, etc). So, be sure to get a history from both sides of the family because each side plays just as important a role in figuring out your risk.

Different cancers hold different risks with regard to genetics. About 12% of women in the general population will develop breast cancer at some point in their lifetime. This considered a high number, so if you have a family history of a few older aunts or grandparents with breast cancer, it does not always cause suspicion for a genetic mutation.

This is different than ovarian cancer, for example, where only 1.5% of women in the general population develop ovarian cancer; if a family member had ovarian cancer, you may qualify for genetic testing.

Genetic counselors are your best resource if you’re considering genetic testing. For more information or to get in touch with a genetic counselor, click here.