HUMAN PARENTAL BEHAVIOR - EVIDENCE FOR GENETIC INFLUENCE AND POTENTIAL IMPLICATION FOR GENE-CULTURE TRANSMISSION

A large sample of adult twins (1117 pairs), who were concordant for ha ving had children were asked to report on their child-rearing practice s. A 14-item version of the Parental Bonding Instrument (PBI) was used to assess rearing practices of parent twins. The two factors of Care and Overprotection, commonly found in other studies, were recovered fr om this analysis of the PBI's parent form. Model-fitting analyses indi cate that human parental behavior is under significant genetic influen ce. Findings further suggest that this influence is sex limited, with a higher heritability in mothers than in fathers, and that it may resu lt partly from the expression of dominant genes. For both PBI factors and both parents, the best-fitting models invariably assumed sex-limit ed genetic effects and unique environmental influences only. Broad her itability ranged from 19% (father overprotection) to 39% (mother care) . These results are interpreted in the broader perspective of gene-cul ture theory.