(Must et al., 2005; Wang, 2002), resulting in a greater likelihood of affiliation with deviant/older peers and substance use. Leptin is involved in both fat metabolism and pubertal development in girls (Li et al., 2005), while its contribution to eating behavior is likely dependent on the cannabinoid system (Di Marzo et al., 2001). Numerous neurobiological mechanisms and respective genes expressed in the brain are potential contributors to variation in CLA, providing basis for testable hypotheses.