Parental representation was assessed with the Parental Bonding Instrument (PBI) in 12 monozygotic (MZ) and 19 dizygotic (DZ) same-sexed twin pairs discordant for DSM-III-R schizophrenia. The schizophrenic twins reported less care and more overprotection from both parents than the non-schizophrenic co-twins. Multiple regression analysis disclosed that the results were independent of sex and age. Furthermore, the analysis demonstrated that whether the twins were monozygotic or dizygotic had no impact on the results. A stepwise discriminant analysis showed that difference in perceived paternal protection was the most important variable distinguishing between schizophrenic probands and their non-schizophrenic co-twins.