Sibling

A sibling is a relative who shares at least one parent with another person, with a male sibling called a brother and a female sibling a sister, and a person with no siblings called an only child. Although some circumstances, such as foster care or adoption, can cause siblings to be raised apart, most societies raise siblings together, which fosters strong emotional bonds and makes siblinghood a distinctive kind of relationship. That bond is often complicated, shaped by factors such as parental treatment, birth order, personality and experiences outside the family. Medically, a full sibling counts as a first-degree relative and a half-sibling as a second-degree relative, reflecting a genetic overlap of fifty and twenty-five percent respectively. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/