to the depression-inducing effects of stressful life events (K. S. Kendler et al., 1995). With methodological advances that allowed twin researchers to model how genetic influences change as a function of the environment (Button et al., 2009), studying gene-environment interaction (GxE) became a popular area of research in behavior genetics (Button, Lau, Maughan, & Eley, 2008; Dick, Bernard, et al., 2009; Dick, Pagan, Holliday, et al., 2007; Dick, Pagan, Viken, et al., 2007; Dick, Rose, Viken, Kaprio, & Koskenvuo, 2001; Dick, Viken, et al., 2007; Harden, Hill, Turkheimer, & Emery, 2008; Purcell, 2002; R. J. Rose, Dick, Viken, & Kaprio, 2001; South & Krueger, 2008).
