Family Size

The size of a family has a significant effect on the relationships between and among its members and may play a pivotal role in the formation of a child's personality.

Family size is a significant factor in child development but must be considered as just one part of a much larger picture. Other factors contribute significantly to the formation of a child's personality, such as the parents’ personality traits; parenting and discipline styles; type and amount of affection expressed; extended family and community ties; and gender, and total age range and spacing of the siblings.

Children in larger families have a greater opportunity to learn cooperation and negotiation at an early age than children of smaller families, as they must learn to get along with siblings. They are often given a higher degree of responsibility for themselves, within the family constellation, and for younger brothers and sisters. In addition, children in large families must cope with the dynamics of sibling rivalry, from which they may learn important lessons about interpersonal relationships that will serve them later in life. This factor, however, may at times be a disadvantage; an older child no longer in a privileged position or a younger child in the shadow (either positive or negative) of older siblings may experience feelings of jealousy, resentment, or decreased self-esteem. Children in large families may adopt specific roles in order to attain a measure of uniqueness and increased parental attention.

Children in small families often receive a greater amount of individual attention and tend to be more comfortable around adults at an early age. They may be overprotected or excessively indulged, which can result in dependent behaviors, lack of initiative, and fear of risk taking or independence. The increased parental attention may also take the form of excessive scrutiny and pressure to live up to other unrealistically high standards and expectations. Research data has shown that only children are more likely than children from larger families to tend toward social isolation and have lessened need for affiliation. They tend to have higher IQs, to perform well relative to the mean group on standardized tests, and are often successful academically. However, only children have also been found to have more behavioral health issues than children from larger families.

See also Affiliation ; Altruism ; Dependent personality disorder ; Family .



Berger, Kathleen Stassen. The Developing Person Through Childhood and Adolescence. New York: Worth, 2012.

Koönig, Karl. Brothers and Sisters: The Order of Birth in the Family: An Expanded Edition. Edinburgh: Floris Books, 2012.

Milevsky, Avidan. Sibling Relationships in Childhood and Adolescence: Predictors and Outcomes. New York: Columbia University Press, 2011.

Shaffer, David R., and Katherine Kipp. Developmental Psychology: Childhood and Adolescence. 2014.

Solomon, Andrew. Far from the Tree: Parents, Children, and the Search for Identity. New York: Scribner, 2012.


Maralani, Vida. “The Changing Relationship Between Family Size and Educational Attainment Over the Course of Socioeconomic Development: Evidence from Indonesia.” Demography 45, no. 3 (August 2008): 683–717.


babycenter. “Family size in America: Are Large Families Back?” (accessed September 18, 2015).

London School of Hygiene & Tropical Medicine. “Science Daily: Small Family Size Increases Wealth of Descendants but Reduces Evolutionary Success.” (accessed September 18, 2015).

Psychology Today. “6 Well-Kept Secrets That Affect Family Size.” (accessed September 18, 2015).

USA Today News. “Does Size Matter? For Today's Families It Does” (accessed September 18, 2015).

(MLA 8th Edition)