In the Finnish Adoptive Family Study of Schizophrenia, Researchers Followed

In the Finnish Adoptive Family Study of Schizophrenia, researchers followed adopted individuals whose biological mothers had schizophrenia. They also followed a control group of adopted individuals whose biological mothers did not have schizophrenia. What was the main finding of the study?

A) The adopted child's biological background had no effect on the rate of development of symptoms of a serious mental disorder.
B) If raised in a psychologically healthy family environment, children with a genetic background of schizophrenia were no more likely to develop schizophrenia than were the children in the control group.
C) The children in the control group were immune to the effects of being raised in a psychologically disturbed adoptive family environment.
D) Even if raised in a psychologically healthy adoptive family, approximately 40 percent of the adopted children with a genetic predisposition for schizophrenia developed symptoms of a serious mental disorder.