Resolving the effects of phenotype and social background on mate selection

Traditional studies of mate selection have not addressed the question of how a marital correlation arises. The common assumption that assortative mating is based on phenotype has not been properly tested. Social background may be a major determinant of choice of spouse. We show how the collection of data on monozygotic (MZ) and dizygotic (DZ) twin pairs and their spouses, and estimation of all possible correlations between the twin pairs and their spouses, will allow these alternative hypotheses to be tested. Power simulations show that it will be feasible to resolve the contributions of phenotype and social background to mate selection for variables such as IQ, education, and attitudes for which the marital correlation is moderately high.