A word from Professor Nancy Segal
Twin research takes place at two levels. First, there are studies that address the unique concerns faced by many twins and their families. Twins wonder if they should head to college together, participate in the same sports or have the same friends. Parents want to know if their twins should be enrolled in the same classroom, should be dressed alike or play the same musical instrument. Research concerning these issues and others is more vital now than ever before, given that twinning rates are increasing in so many nations. Second, many researchers apply the classic twin method to learn the extent to which our behavioral, physical and medical characteristics are shaped by genetic and environmental influences. Simply by comparing the degree of similarity between samples of identical and fraternal twin pairs, scientists have learned so much about who we are and how we got that way. Many developmental questions still need answers and twins remain the best route to their discovery.
Nancy L. Segal, Ph.D.
Professor of Psychology and Director, Twin Studies Center
California State University, Fullerton