Nancy Segal is a professor of psychology at California State University, Fullerton and the director of the Twin Studies Center, which she founded in 1991. Segal has authored approximately 200 scientific articles and book chapters on the study of genetics and twins. She has also published many books on the subject of twin research, including, “Born Together-Reared Apart: The Landmark Minnesota Twin Study,” “Twin Mythconceptions: False Beliefs, Fables, and Facts About Twins,” and her most recent, “Accidental Brothers: The Story of Twins Exchanged at Birth and the Power of Nature and Nurture.”