Leonard Heston Conducted an Adoption Study of the Possible Causes

Leonard Heston conducted an adoption study of the possible causes of schizophrenia. What was the major finding in his study?

A) There was no evidence of a genetic influence on schizophrenia.
B) Adopted individuals had higher rates of schizophrenia regardless of the mental health status of their parents.
C) The environment one grows up in has a much greater impact on the incidence of schizophrenia than do genetic factors.
D) Adopted children born to mothers who were schizophrenic developed schizophrenia at a higher rate than did children born to normal mothers.