Second-degree relative

Second-degree relative refers to a family member who shares about 25% of their genetic material with a particular individual. This includes an individual's grandparents, grandchildren, aunts, uncles, nephews, nieces, and half-siblings.

Definition

A second-degree relative is defined as a blood relative which includes the individual's grandparents, grandchildren, aunts, uncles, nephews, nieces, and half-siblings. This is in contrast to a first-degree relative, which includes the individual's parents, full siblings, and children.

Genetic Relation

Second-degree relatives share approximately 25% of their genetic material. This is due to the fact that humans share 50% of their genetic material with each of their parents, who in turn share 50% of their genetic material with their own parents and siblings. Therefore, an individual shares 25% of their genetic material with their grandparents, aunts, uncles, and half-siblings, and also with their grandchildren and nieces or nephews.

Medical Relevance

The degree of relation has relevance in medical and genetic contexts, as the likelihood of sharing genetic traits, including hereditary diseases, increases with the degree of relation. For example, if a first-degree relative has a hereditary disease, the risk of an individual developing the same disease is higher than if a second-degree relative has the disease.

See Also

• First-degree relative
• Third-degree relative
• Cousin
• Genetics
• Hereditary disease

Second-degree relative Resources
Need Help Finding a Doctor? WikiMD's DocFinder can help find general and specialist physicians.	Latest articles Most recent articles Ongoing trials.