Prepared by Elisabeth Lindsay.
A descendant is the child, grandchild, or great-grandchild, etc. of an ancestor, a child born of a later generation. One ancestor can have many descendants, as multiple children are born who may then go on to have multiple children of their own. Direct line descendants are those descended from the same ancestor such as a father and son, grandfather and grandson, etc. Collateral line descendants are persons descended from a common ancestor such as children in a family who share the same parents, or cousins in a family who share the same grandparents. Each generation represents a degree of blood relationship, one generation to another; first degree relatives include one's parents, offspring, and siblings.
An understanding of family lineage, including descendant relationships is an aid genealogical research, identifying one's place in the family and the relationship of others one to another. The goal of most family researchers is to trace their direct-line ancestry, although collateral-line research also plays a role. Understanding descendant relationships is also important for understanding the line of succession in some families as pertains to inheritance, disputes, and the transfer of power.