Fictive kinship is a term used by anthropologists and ethnographers to describe forms of kinship or social ties that are based on neither consanguineal (blood ties) nor affinal ("by marriage") ties. It contrasts with true kinship ties. To the extent that consanguineal and affinal kinship ties might be considered real or true kinship, the term fictive kinship has in the past been used to refer to those kinship ties that are fictional, in the sense of not-real. Invoking the concept as a cross-culturally valid anthropological category therefore rests on the presumption that the inverse category of "(true) kinship" built around consanguinity and affinity is similarly cross-culturally valid. Use of the term was common until the mid-to-late twentieth century, when anthropology effectively deconstructed and revised many of the concepts and categories around the study of kinship and social ties. In particular, anthropologists established that a consanguinity basis for kinship ties is not universal across cultures, and that—on the contrary—it may be a culturally specific symbol of kinship only in particular cultures (see the articles on kinship and David M. Schneider for more information on the history of kinship studies). Stemming from anthropology's early connections to legal studies, the term fictive kinship may also be used in a legal sense, and this use continues in societies where these categories and definitions regarding kinship and social ties have legal currency; e.g. in matters of inheritance. As part of the deconstruction of kinship mentioned above, anthropologists now recognize that—cross-culturally—the kinds of social ties and relationships formerly treated under the category of "kinship" are very often not necessarily predicated on blood ties or marriage ties, and may rather be based on shared residence, shared economic ties, nurture kinship, or familiarity via other forms of interaction. In sociology of the family, this idea is referred to as chosen kin, fictive kin or voluntary kin. Sociologists define the concept as a form of extended family members who are not related by either blood or marriage. The bonds allowing for chosen kinship may include religious rituals, close friendship ties, or other essential reciprocal social or economic relationships. Examples of chosen kin include godparents, adopted children, and close family friends. The idea of fictive kin has been used to analyze aging, foreign fighters, immigrant communities, and minorities in modern societies. Some researchers state that peers have the potential to create fictive kin networks. Examples Types of relations often described