nonrelative

Nonrelative is an adjective and noun used to describe a person who is not related by blood or marriage to another person. In everyday language it designates someone outside a family network. The term is used in various fields to distinguish individuals who have no established familial ties.

In social science and demography, nonrelatives are contrasted with relatives to study patterns of cohabitation, caregiving, and social support. The label is often provisional because relationships may be unknown, unrecorded, or complicated by adoption, step-relationships, or cultural definitions of kinship. Distinctions between relatives and nonrelatives can affect access to resources, obligations, and social norms.

In genetics and biomedical research, nonrelatives (or unrelated individuals) are important for certain study designs, such as genome-wide association studies, to reduce confounding from kinship. Relatedness is quantified using kinship coefficients or identity-by-descent measures, which help ensure sample independence and interpretability of statistical results.

In child welfare and law, nonrelative caregivers are adults who are not related to the child, as opposed to relative or kinship caregivers. Policies may prioritize relatives when possible but allow nonrelatives when relatives are unavailable, affecting placement, funding, and legal rights.

Limitations of the term include incomplete knowledge of family connections, evolving cultural definitions of kinship, and privacy concerns around genealogical data. Genetic testing can reveal unexpected relatedness, potentially altering previously assigned nonrelative status. Related terms include unrelated, kin, kinship, consanguinity, and family. The concept emphasizes absence of established family ties rather than formal legal status.