Preliminary evidence already points to important genetic differences in xenobiotic metabolism with downstream impacts on intrauterine growth (Price, Grosser, Plomin, & Jaffee, 2010) and behavior (Knopik, McGeary, Nugent, Francazio, & Heath, in press) Further characterization of these samples from an epigenetic standpoint could explain additional variance in behavioral outcomes while simultaneously identifying potentially targetable mechanisms to reduce such impacts.