- Any relative who is one meiosis away from a particular individual in a family (i.e., parent, sibling, offspring)
Definition from: GeneReviews
from the University of Washington and the National Center for Biotechnology Information
- A first degree relative is a family member who shares about 50 percent of their genes with a particular individual in a family. First degree relatives include parents, offspring, and siblings.
Definition from: Talking Glossary of Genetic Terms from the National Human Genome Research Institute
Related discussion in the Handbook
See also Understanding Medical Terminology.