Our parents and grandparents share family values, traditions and heirlooms with us to help define who we are. They also pass along genes that determine our eye color, height and risk for developing certain medical conditions.

Decades of experience have shown us that inherited risks play a large role in rare diseases but a small role in common diseases, such as cancer. The impact of individual behaviors like smoking, lack of exercise and unhealthy diet is often a greater factor in causing common diseases than inherited genetic risk.

Thanks to biomedical research, new robotic instruments and other advances, we are rapidly increasing our understanding of the genetic and molecular factors that cause disease, even when the disease is not caused by inherited genetic factors. This in turn has dramatically quickened the pace of development of new treatments and tests that can improve outcomes.

For example, a woman with breast cancer can now have a test to tell her whether or not a tumor bears a genetic trait. If she tests positive for producing too much of a protein called HER-2, she is a good candidate for a drug called trastuzumab (brand name Herceptin), which controls excess HER-2 and improves her survival.

Researchers and clinicians hope to build on these successes in developing targeted and effective therapies so that medicine can become more personalized for each patient.

To fulfill personalized medicine’s promise, my agency, the Agency for Healthcare Research and Quality (AHRQ), continues to create new knowledge, evaluate existing knowledge and assist in disseminating accurate information and implementing evidence-based recommendations on the appropriate use of genomic tests in clinical practice.

For example, we are partnering with the Centers for Disease Control and Prevention (CDC) to create reports that examine the use of genetic tests, which examine inherited predispositions to certain diseases, and genomic tests, which look at groups of genes, how active they are, and whether this activity can influence how a disease is likely to progress and respond to treatment.

The reports are then used to help develop evidence-based recommendations on how genetic or genomic tests should be used in medical practice. We have already released several reports that address these types of tests for diseases including ovarian, breast and colorectal cancer; depression; and blood clots.

The reports have shown major gaps in our knowledge of the outcomes of genetic testing. As a result, AHRQ, the CDC and the National Institutes of Health are partnering to improve the evidence base for genetic tests. One new evidence report, for example, weighs in on the outcomes of family history evaluation for common diseases.

The potential of genetic-based personalized medicine is just coming into focus. If your doctor recommends that you take a test to determine your inherited risk for a disease, you should ask questions, such as:

• Why do I need this test?

• What would “positive” results mean for me?

• What are my choices if a test is positive?

• How accurate is this test in predicting future risk?

• How important is my inherited risk in contrast with other factors, such as my health behaviors?

Having the answers to these questions will help you be an active partner in your health care.

I’m Dr. Carolyn Clancy, and that’s my advice on how to navigate the health care system.

Carolyn M. Clancy, a general internist and researcher, is an expert in engaging consumers in their health care. She is the director of the U.S. Agency for Healthcare Research and Quality.