Parentage in a family tree
Normal parentage is two natural parents. Unusual parentage is three or more physical parents. Rare parentage is having parents that are a mix of several genetic sources, none of which are singular people.
Adoption: Most people have just two parents, whether they are married or not. In some cases a person may have adopting parents and natural parents. All these parents, whether adopting or natural, do, or did, have a physical presence on earth.
Genetics: With advances in medical science, a person could have multiple parents because of mixing genetic materials from different people.