Only child

An only child is a person with no siblings. The term describes a family position, not necessarily a person who grew up without other children in the household.

Birth order: The position a person occupies among siblings, often studied in relation to development and family roles. Only-child status is a distinctive position in birth-order discussions, though it includes no sibling rank.
Personality development: The formation and change of characteristic patterns of thought, feeling, and behavior across a person's life. Studies ask whether growing up without siblings produces distinctive personality patterns.
Sibling: A person who shares at least one parent with another person. The presence or absence of siblings defines the basic boundary of only-child status.
Firstborn: The child born earliest among a person's siblings. A firstborn has a sibling position; an only child has no siblings to rank against.
Stereotype: A widely held, simplified belief about the traits of members of a group. Popular claims about only children often turn individual differences into a shared personality stereotype.
Socialization: The process through which people learn norms, roles, and ways of participating in society. Sibling-free childhood is one setting among many in which social skills and expectations develop.
Nuclear family: A family unit commonly consisting of parents and their children. Only-child status is often discussed within this household model, though families take many forms.
Middle child: A child with at least one older and one younger sibling. Middle-child roles depend on sibling relationships absent from only-child family structure.
Family systems theory: An approach that understands people through patterns of interaction within family relationships. It frames only-child experience through family dynamics rather than sibling count alone.
Peer group: A group of people of similar age or status who influence one another's behavior and identity. Peers can provide frequent childhood interaction that siblings might otherwise supply at home.

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One-child policyBroader topic: The policy created a large generation of people who grew up without siblings.