"Understanding how DNA makes us who we are will teach us to be more tolerant of each other."
Robert Plomin is an American psychologist and geneticist, who has made important contributions to the study of identical twins. Plomin's study of "non-shared environment" has shown that members of one and the same family can develop very differently due to environmental factors. Plomin's most recent book is called Blueprint: How DNA Makes Us Who We Are. In it, Plomin argues that genetic factors play a large role in determining psychological traits such as intelligence.