 Biological parents are commonly distinguished from social parents, who rear the child and are socially perceived as responsible for it. Adoptive parents, or parents who rear children created with donated gametes and gestated by a third party, are social, but not biological, parents. (Biological parents need not be social parents, as biological parents give up children for adoption, donate gametes, or work as gestational parents.) The category of social parent presents borderline cases when a given community does not socially recognize those rearing a child as parents. This might occur with a mother’s unmarried partner, two friends rearing children together, other relatives like grandparents rearing the child, or when a community participates in child-rearing. Legal and moral criteria for the acquisition of parental rights and responsibilities should clearly designate whom society should recognize as having them.