Religious affiliation in twins and their parents: testing a model of cultural inheritance.

The transmission of religious affiliation is analyzed in a sample of 3810 Australian twin pairs and their parents. Twins were classified by sex, zygosity, and whether they were living together or apart. Analysis of twin, spousal, and parent-offspring resemblance shows that several different forms of cultural inheritance operate jointly in the transmission of religious affiliation. Model-fitting methods show that (1) the environmental influence of mothers is significantly greater than fathers; (2) there is a substantial amount of assortative mating for religious affiliation; (3) there is a substantial environmental component shared by twins which does not depend on parental religious affiliation; (4) religious affiliation attributed to parents by their children is biased by the religious affiliation of the children; (5) nongenetic effects on the expression of religious affiliation are much greater in twins living together; and (6) a moderate genetic effect on religious affiliation is expressed in females but only when twins live apart. Implications of the method and findings are discussed for other aspects of family resemblance, including the analysis of social and occupational mobility.