ABSTRACT

The nature of twinning often places twins at risk for developmental and behavioral problems. The longterm research programs of the Louisville Twin Study have contributed significantly to the investigation of risk factors in the early years. The Louisville Twin Study is a research project in the Department of Pediatrics at the University of Louisville. It began in the mid-1950s as one of the international studies of child development, with an emphasis on the longitudinal study of how genetic and environmental factors influence physical growth and mental development. In 1976 the main focus of the program became the assessment of temperament in infant twins, with personality, language and behavior also studied. Twins, triplets, quadruplets, siblings of twins and parents of twins were assessed, and procedures included hospital observations, laboratory observations, physical measures, questionnaires, interviews and parental reports.