Twin Research and Human Genetics


The Southern California Twin Register at the University of Southern California: III

Laura A. Bakera1 c1, Catherine Tuvblada1, Pan Wanga1, Karina Gomeza1, Serena Bezdjiana1, Sharon Niva1 and Adrian Rainea2

a1 Department of Psychology, University of Southern California, Los Angeles, CA, USA

a2 Departments of Criminology and Psychiatry, University of Pennsylvania, Philadelphia, PA, USA


The Southern California Twin Register at the University of Southern California (USC) was initiated in 1984 and continues to provide an important resource for studies investigating genetic and environmental influences on human behavior. This article provides an update on the current register and its potential for future twin studies using recruitment through school district databases and voter records. An overview is also provided for an ongoing longitudinal twin study investigating the development of externalizing psychopathology from childhood to young adulthood, the USC Study of Risk Factors for Antisocial Behavior. Characteristics of the twins and their families are presented, including recruitment and participation rates, as well as attrition analyses and a summary of key findings to date.

(Received September 11 2012)

(Accepted October 13 2012)


  • twins;
  • Southern California;
  • anti-social behavior;
  • externalizing psychopathology


c1 address for correspondence: Laura Baker, Department of Psychology (SGM 501), University of Southern California, 3620 S. McClintock Ave., Los Angeles, CA 90089-1061. E-mail: