Birth Order

Birth order refers to the order in which siblings are born into a family. Although siblings may be ranked numerically according to their order of appearance, four positions typically are recognized: first, middle, youngest, and only child. Only one sibling may occupy the first, youngest or only positions, but many children can be classified as middle.

Alfred Adler (1927, 1956) was the first psychologist to theorize about the effects of birth order on personality development (Stewart and Stewart 1995). Adler (1927) believed that parents' responses to their children were affected by the order of each child's birth into the family. This differential treatment of each child based on birth order position was believed to influence the child's developing personality. Since the inception of Adler's theories, more than 1,700 journal articles and dissertations have been written about birth order and its relationship to a wide variety of psychological topics. Two of the most popular areas of inquiry include personality traits and intellectual achievement (Rodgers et al. 2000; Stewart and Stewart 1995).