Why study twins?
Studying twins allows us to identify both genetic and environmental influences on child development. Identical twins share 100% of their genes and fraternal twins share, on average, 50% of their genes. We can look at behavior relationships between twin pairs and estimate the heritability of a certain trait or behavior. For example, if identical twins are more similar than fraternal twins on a given trait, we estimate that there is a stronger genetic influence on that trait. Twin methodology provides us with sophisticated analysis of genetic, environmental, and interaction effects on child development and related risk and protective factors.
