Descendants Law & Legal Definition. Descendants are those who are the issue of an individual, such as children, grandchildren, and their children, to the remotest degree. Descendants are those in a descending line of birth from an individual, rather than an ascending line, such as to the parents of the individual.Determining who a person's descendants are is commonly necessary to determine who is entitled to share in the estate of a person who dies without a will.State statutes of descent and distribution, which vary by state, provide for the surviving spouse and/or descendants to share in the estate of the deceased.etermining who a person's descendants are is commonly necessary to determine who is entitled to share in the estate of a person who dies without a will. State statutes of descent and distribution, which vary by state, provide for the surviving spouse and/or descendants to share in the estate of the deceased.