A recent report published in the American Journal of Medical Genetics (Smith et al. 2014) describes a methodical comparison of buccal cells and blood as potential surrogates for brain tissue in epigenomic studies aimed at assessing the methylation status of DNA. The methylation patterns of specific genes are thought to be biomarkers for a variety of psychological disorders and may be the result of such factors such as childhood abuse, malnutrition, and traumatic stress. The authors find that DNA methylation patterns in buccal cells are more similar than blood to those of brain tissue. Certainly it is an attractive notion that permanent changes in the methylation patterns of the genetic code are at least partially responsible for some chronic psychiatric and behavioral traits, but the idea that a simple cheek swab can help unravel these mysteries even better than a blood sample is the part we find the most fascinating.