Grandparents are the parents of a person's father or mother – paternal or maternal. Every sexually-reproducing creature who is not a genetic chimera has a maximum of four genetic grandparents, eight genetic great-grandparents, sixteen genetic great-great-grandparents, 32 genetic great-great-great-grandparents, 64 genetic great-great-great-great-grandparents, etc., although the numbers will be lower in cases of pedigree collapse.
