Examination of Hypotheses Concerning Birth Order and Sibship Size by Multivariate Analysis of a Representative Young Adult Population

Abstract

Siblings growing up in the same family differ considerably in physical appearance, personality, intelligence, school achievement, and other characteristics. It is a basic human need to explain these differences. If the general assumption is true that mainly environmental conditions influence human development, birth order should be of paramount importance. Being one of the few clearly defined environmental factors, it is open to scientific investigation.