Gene-environment correlations can be characterized as evocative, active, or passive (Plomin 1990; Neiderhiser et al. 2004). Evocative gene-environment correlations occur when genetically influenced characteristics of children, such as disruptive behaviors, evoke responses from the environment, such as harsh parenting. Active gene-environment correlations occur when a child selects environments, such as deviant peer groups, that are correlated with his or her genetically influenced characteristics, such as impulsivity. Evocative and active gene-environment correlations both reflect a correlation between children’s genes and their environmental experiences and are indistinguishable in a twin study (Neiderhiser et al. 2004); therefore, they are both referred to as nonpassive gene-environment correlations in the present study. In contrast, passive gene-environment correlations reflect parents’ tendency to parent in a certain way and children’s vulnerability to behave in a certain way both being influenced by a common heritable vulnerability. For example, a heritable vulnerability to antisocial behavior may both predispose parents to maltreating their children and lead children to develop conduct problems. Child effects on a parenting behavior refer to any quality of a child (e.g. behavior, health, age, gender, etc.) which is associated with that parenting behavior. Genetically-mediated child effects are synonymous with nonpassive gene-environment correlation.
