This is a reply to a critique by Karon and Saunders (9) of the Eysenck and Prell work on the inheritance of neuroticism (6). This paper is a curious combination of sophisticated statistical analysis and argument by irrelevant association. Thus the authors mention the fact that we found a strong heredity predisposition but go on to say that “the results are so much at variance with general clinical experience that doubts arise in the minds of many psychologists … particularly those who have investigated, in a therapeutic situation, the source and development of neurotic reactions”. The authors do not indicate how it is possible through general clinical experience or in the therapeutic situation, to find an answer to one of the most difficult and complex problems in the whole field of psychology. Whether neurotic predisposition is largely inherited or has little hereditary basis, would not seem to be capable of being discerned simply by giving psychotherapy to a few neurotics.