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First Degree Relative
A first-degree relative is a family member who shares about half of their genetic information with specific other individuals in their family. First-degree relatives include an individual’s parents, siblings and offspring.
First-degree relative. If you ever meet with a genetic counselor or other genetics professional, to talk about your family history, the counselor will probably start by asking you about your first-degree relatives. These close relatives are the people in your family with whom you share the most DNA.
Genetic Counselor
Precision Genomics Section