Dr. Nancy L. Segal received a B.A. degree from Boston University (1973) and an M.A. degree (1974) and Ph.D. degree (1982) from the University of Chicago. She is currently Professor of Developmental Psychology and Director of the Twin Studies Center, at California State University, Fullerton. She was recognized as CSU Fullertonšs 2004-5 Outstanding Professor of the Year, as well as  the 2004-5  Distinguished Professor in Humanities and Social Sciences. Dr. Segal also received the 2005 James Shields Award for Lifetime Contributions to Twin Research from the Behavior Genetics Association and International Society for Twin Studies.


Dr. Segal is the author of Indivisible by Two: Lives of Extraordinary Twins (Cambridge, NA: Harvard University Press). This collection of essays on twelve twin, triplet and quadruplet sets brings together humanity and science in a unique way.  She is also the author of Entwined Lives: Twins and What They Tell Us About Human Behavior (NY: Dutton, 1999). This comprehensive survey of twins and twin research includes chapters on the biology of twinning, twin research methodology, findings on intelligence, personality, mental disorders and athletic prowess, studies of twin relationships, information on twins raised apart, findings on "pseudo-twins" or same-age unrelated children raised together, non-human twinning, new fertility treatments, life histories of noteworthy twins, legal issues involving twins, conjoined twins and a timely survey of nature-nurture issues. Dr. Segal is also editor (with G.E. Weisfeld and C.C. Weisfeld) of Uniting Psychology and Biology: Integrative Perspectives on Human Development (Washington, D.C.: American Psychological Association Press, 1997). This book, which resulted from a festschrift in honor of her mentor Professor Daniel G. Freedman at the University of Chicago, brings together a series of current papers on behavioral-genetic, ethological, cultural and evolutionary approached to human behavior.


Dr. Segal is a Fellow of the American Psychological Association, American Psychological Society and Western Psychological Association.  She has been inducted into the Collegium of Distinguished Alumni at Boston University.  Dr. Segal is an Associate Editor for the journal Twin Research and Human Genetics and was Contributing Research Editor for Twins Magazine from 1984-1998 and is a member of the Advisory Board for the Center for Loss in Multiple Birth. She served as Assistant Director of the Minnesota Center for Twin and Adoption Research, in the Department of Psychology at the University of Minnesota, in Minneapolis, 1985-1991.  She has appeared on Good Morning America, the Oprah Winfrey Show, Dateline NBC and the Today Show, in addition to other nationally and locally televised programs. Her research interests include genetic and environmental influences on human behavior, especially social relationships and bereavement.  Her research program includes twin and adoption studies that are specially designed to address problems and issues concerning human development in general, and twin development in particular.


Dr. Segalšs papers have appeared in prestigious journals, such as American Psychologist, Child Development and Science. She has received research grants from the National Science Foundation, the American Psychological Association and the Olfactory Research Fund, Ltd. She was named a Dean's Faculty Scholar for the Spring, 1999 semester. She has addressed the National Organization of Mothers of Twin in St. Louis, in July, 1999, the New Zealand Organization of Mothers of Twins in the Fall, 2000, and will be returning to New Zealand in the Fall 2007.


Over the years Dr. Segal has served as an expert witness on legal cases involving twins, in particular wrongful death, injury, medical negligence, and custody. A paper reporting this work was published in a special issue of the journal Law and Human Behavior. Additional details about this unique area of study appear in her book, Entwined Lives.


Each year Dr. Segal offers a seminar on behavior genetics and evolutionary psychology to graduate students in the Department of Psychology. She has sponsored both undergraduate and graduate research projects involving original twin research designs and methods.