gene-environment correlation (Purcell, 2002). A genetic correlation is the amount of overlap in the genetic influences on two phenotypes and ranges from −1 to +1; similar types of correlations (i.e., overlap) can occur for shared and nonshared environmental influences. Therefore, we will use the more accurate term “biometrical moderation” to refer to the analyses conducted in these studies; this term better captures the goal of this study—to determine whether the magnitude of genetic and environmental influences on internalizing pathology depends on marital quality (gene-environment interaction), and the extent to which influences acting on internalizing pathology also exerted influences on marital quality (gene-environment correlation).
