Q. My grandson asked me to participate in a family tree about our medical conditions. He wants to ask me questions about my health, but I'm a pretty private person. I don't know about this. What do you think?

I respect your reluctance to discuss personal matters with your grandson. However, the information you have to share with him would benefit your entire family and future generations. Perhaps your grandson could submit questions in writing and you could answer them in the same way. That might help avoid uncomfortable moments.A medical family tree or family health history (also known as a medical genealogy) is like the ones genealogists prepare, but it also includes all the maladies suffered by members of the family. A medical tree can reveal patterns and help everyone in a family choose medical tests, diagnose diseases, prevent medical problems and assess health risks.Many of the causes of our illnesses are inherited from our ancestors. Almost a third of known diseases have genetic links. These include colon cancer, heart disease, alcoholism and high blood pressure.Family gatherings are an opportunity to get started on a medical genealogy. If you want to prepare one, you should write down your questions in advance. You should ask enough questions and the right questions to make a medical genealogy useful to members of the families and their doctors.The following is important information about each family member - living and dead - that should be included in a health history. Frame your questions to elicit this data.• Birth and death dates.• Cause of death.• All medical conditions with dates and outcomes. Include anything outside the norm, not just serious diseases. Don't forget problems such as allergies, vision and hearing difficulties.• Birth defects.• Mental health problems.• Lifestyle description. This would include information about smoking, drinking, diet, obesity and exercise.• Racial and ethnic background. Some medical conditions are more common in certain groups of people.If you want to prepare a medical genealogy, an extremely helpful resource is "My Family Health Portrait," an online tool provided by the U.S. Surgeon General. You can find it at hhs.gov/familyhistory/portrait/index.html.The tool guides you through a series of screens that helps you compile information for each of your family members. Then you get a graphic printout with the information organized in a diagram or a chart. The tool allows users to return and update information.I used the online tool to do my own family tree. It was a simple process that produced a valuable report.If you want something more basic, you can get a free five-generation ancestor chart at familytreemagazine.com/forms/download.html#.This chart is designed for a standard genealogy, but it's a good basic document to create your own medical family tree.The information in a medical tree provides indications, not guarantees that family members will inherit problems from their ancestors. How you take care of yourself is a major influence on your health.(My next column will be about genetic testing.)The views of the author do not necessarily state or reflect those of the Times News.