How to Compile your Medical Family Tree


Understanding the warning signs in your family's medical history can help you prevent hereditary health problems before they occur. Your physician or a genetic counselor will examine your family tree for evidence of genetic conditions and advise you of your options for screening and diagnosis.

Begin your medical family tree by making a list of your blood relatives, both living and deceased:

•First-degree relatives: your parents, siblings, and children
•Second-degree relatives: your grandparents, aunts, uncles, nieces, nephews, and half-siblings
•Third-degree relatives (if known): great-grandparents, first cousins, great-aunts and great-uncles

Jot down approximate birth dates and death dates wherever you can. Do not include people who are related to you by marriage or adoption.

Don't worry if there are gaps in your family tree. It's common not to know much about second- and third-degree relatives. Your parents or siblings may be able to supply some of the missing information when you speak to them.

Talking to your family about their health

Family medical history is so important that the Surgeon General declared Thanksgiving to be National Family History Day, in the hope that Americans will use family gatherings as an opportunity to learn about their family health history.

However, many families are reluctant to discuss past illnesses in a group setting or even one on one. Privacy concerns, shame, and the desire to avoid painful memories can erect a wall of silence and prevent the sharing of important medical information.

Remember, it's okay to ask questions, even if medical matters aren't normally discussed in your family. You have a right to information that will help you make decisions about your healthcare and your children's. Once you start the conversation, you may be surprised at how some people open up.

You know your family best. Consider whether they will be more comfortable talking in a group, in private, on the phone, or by e-mail. If you think some of your relatives will be more receptive than others, approach them first. They may be able to tell you about other family members' illnesses as well as their own.

Prepare your questions ahead of time and think about how to raise them without causing pain or offense. Explain why you are seeking this information and how it will help you protect yourself and your children from illness. Assure your relatives that their personal medical details will not be misused or shared without their permission.

What to look for in your family history

1. Ethnicity

It's important to know where your ancestors came from because some genetic disorders occur more frequently in one ethnic group than in others: Tay-Sachs is more common among Ashkenazi Jews and French Canadians, Sickle Cell among African Americans, and Beta-Thalassemia among Greeks and Italians, to name just a few.

[Pop-up link to table: populations with increased risk of genetic disorders]

Try to trace your ethnic heritage on both your mother's and your father's side of the family, and note in particular whether your parents, grandparents, or great-grandparents come from a higher-risk ethnic group.

2. Health Problems

Knowing the illnesses that have affected your parents, siblings, and other relatives will help your genetic counselor assess your risk for an inherited disorder. Starting with your first-degree relatives and moving outwards, look for evidence of:

•Pregnancy losses or stillbirths
•Mental retardation or developmental delays
•Birth defects
•Children who died young
• Positive test results for a genetic condition
• Cancer
• Heart disease, high blood pressure, or stroke
• Diabetes
• Asthma
• Mental illness
• Kidney disease
• Alcoholism
• Vision or hearing loss at a young age

Try to collect as many details as you can about any illness you discover. Write down:

• The affected relative's sex and date of birth
• Relationship to you (e.g. maternal aunt, first cousin on father's side)
• Age at diagnosis
• Age at death and cause of death (if deceased)
• Details of the health problem
• Whether the affected family member smoked, was overweight, or had a history of substance abuse

The more you know about your family's medical history, the better you'll be able to take charge of your own health and your children's.

What if I am adopted?

Depending on the laws in the state where you were adopted, you may have little or no access to medical information about your biological family. Even if you are able to obtain records, they are likely to be outdated and incomplete.

• Gather whatever information you can. For instance, you may know or be able to guess your birth parents' ethnicity.
• Talk to your adoptive parents. They may have medical information about your biological parents or siblings that they haven't shared with you before.
• Pay attention to your personal medical history and your partner's. If you have experienced pregnancy losses or had difficulty conceiving, these could be signs of an inherited health problem.
• Make sure your doctor and genetic counselor know you are adopted. They can help you determine whether screening is right for you.

What to do with the information you collect

The Surgeon General's Family History Initiative provides an online tool that will help you gather your family medical history and generate your family health portrait.

Your physician or a genetic counselor will be able to interpret the data in your family tree and determine whether genetic tests are warranted.

Keep any notes you made during your investigations. They can help you answer any additional questions your healthcare provider might ask upon reviewing your family tree.

For more information and resources about family health history:
New England Journal of Medicine Article on Family History
CDC Family History Tools and Resources
Printable CDC Fact Sheet on Family Health History
Michigan's Genetic Resource Center
Genetic Alliance Family Health History Tool
U.S. Surgeon General's Family History Initiative
My Family Health Portrait: A tool from the U.S. Surgeon General
Your Family History, Your Future — National Society of Genetic Counselors