Dr Torrey questions the results in our article on risks in the offspring of Fischer's Danish schizophrenic twins because of allegedly unsatisfactory basic data. His allegations cannot be substantiated, as any reader may see from the article itself.
Dr Torrey states that our "conclusions are based on the offspring of four normal co-twins." The conclusions are based on the comparison between the risks for schizophrenia in the offspring of a national sample of systematically ascertained monozygotic and dizygotic twin pairs concordant and discordant for schizophrenia, all investigated catamnestically as far as possible by our late colleague Margit Fischer, MD, who was a senior clinician and an internationally renowned research psychiatrist, and updated 18 years after Fischer's fieldwork by us. By the nature of such material the investigation cannot be ideal and complete, but, as it stands, presents the best possible use and is comparable with the twin studies in the