Granparents are the father or mother of a person's own father or mother, being respectively a grandfather (also colloquially grandpa, grandad, or gramps, among other less common titles) and grandmother (also grandma, grandam, granny, among other less common titles). By virtue of being a grandparent, one is also a parent. Everyone has a maximum of four genetic grandparents, eight genetic great-grandparents, sixteen genetic great-great-grandparents, etc. Sometimes these numbers are lower and in the case of having only two or three grandparents sibling or half-sibling incest would be involved.