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Segal, Nancy L.

Professor of Psychology

Director, Twin Studies Center

Psychology Department

Office: 657-278-2142

Department: 657-278-3514



Nancy L. Segal received a B.A. degree in psychology and literature from Boston University (1973), and M.A. (1974) and Ph.D. (1982) degrees in the social sciences and behavioral sciences from the University of Chicago. From 1982-1991 she was a postdoctoral fellow and research associate at the University of Minnesota, affiliated with the well-known Minnesota Study of Twins Reared Apart. She is currently professor of psychology at California State University, Fullerton and director of the CSUF Twin Studies Center, which she founded in 1991. Segal has authored more than 200 scientific articles and book chapters, as well as several books on twins. Her latest book, Born Together-Reared Apart: The Landmark Minnesota Twin Study (2012, Harvard University Press) won the 2013 William James Book Award from the American Psychological Association. Her other books include Someone Else’s Twin: The True Story of Babies Switched at Birth (2011), Indivisible by Two: Lives of Extraordinary Twins (2007) and Entwined Lives: Twins and What They Tell Us About Human Behavior (2000). She is currently working on two new books, one on misconceptions surrounding twins and twin research, and the other on the life histories of two sets of identical Colombian twins who were inadvertently exchanged at birth. The professor has received several international awards, including the James Shields Award for Lifetime Contributions to Twin Research (International Society for Twin Studies) and the International Making a Difference Award (Multiple Births Canada). She is the 2016 recipient of the Wang Family Excellence Award from the California State University for “exemplary contributions and achievement.” Shel has contributed to, and been featured in, national and international print media, most recently the New York Times (“The Closest of Strangers,” May 2014; “Holding a Mirror to Their Natures,” August, 2014; “The Mixed-Up Brothers of Bogotá, July, 2015; and “The Whites of Our Eyes,”

Areas of Knowledge:
  • Twins
  • Twin studies
  • Adoption research

  • Children's Issues
  • Psychology
  • Twin Studies