birth order

n. The ordinal position of a child in a family with more than one child. Birth order is a secondary variable relating to many others which have been found to have influence on family dynamics and the differing experience of each child in a family that affect personality, academic achievement, sexual orientation, and hormonal levels. Numerous theorists have supposed birth order is an important variable in personality development, but empirical studies have found it to be a weak predictor whose affects are mediated through other variables.