The Easterlin hypothesis (Easterlin 1969, 1973) states that the positive relationship between income and fertility is dependent on relative income. The hypothesis as formulated by Richard Easterlin presumes that material aspirations are determined by experiences rooted in family background. If income is high relative to aspirations, individuals will tend to have more children. If income is scarce relative to aspirations, they will be hesitant about having more children, since children compete for resources. Children are normal goods once this influence of family background is controlled.