In general, you will find the health information about blood relatives, back two to three generations, from both your mother's and father's families to be helpful to you. These relatives are:
- half-siblings (because they share a parent with you)
Even if these relatives have died, their health information may be important to you.
Do not include information about anyone not related to you by blood, including your spouse's family, or step-parents or step-siblings or children. Since they are related only by marriage, their health history will not directly affect your health.