 As you sit, sipping your morning cup, or two, of coffee, here's something to consider. The amount of coffee you drink each day may be encoded in your DNA. Given its popularity and complex chemistry, the health benefits of coffee have long been studied. These include protection against diabetes, Alzheimer's disease, and even some types of cancer. Despite all of these benefits, however, the one coffee drinkers are most often after the pick-me-up from caffeine. And that craving for caffeine, it turns out, may be driven by genetics. To further unravel this relationship, a European research team looked closely at the coffee-drinking habits of two study populations in Italy and one in the Netherlands. The researchers recorded how many cups each of the almost 3,000 people surveyed consumed per day. Using genomic techniques and statistical analyses, they looked for associations between the amount of coffee consumed and the presence of certain genetic variants. One association stuck out. Coffee consumption appeared to be strongly correlated with the expression of the PDSS2 gene, a known player in caffeine metabolism. This link provides clues to why some people drink more coffee than others, and points specifically to how individuals break down caffeine. A cascade of chemical reactions occurs as the liver attempts to metabolize these energy-boosting molecules, a process which appears to be regulated by the PDSS2 gene. When the gene is expressed at low levels, caffeine is removed from the bloodstream and broken down quickly, resulting in intensified cravings and tempting some to reach for another cup. While these findings provide a genetic link to coffee consumption, they may have broader implications as well. Because many genes responsible for metabolizing caffeine also play a role in breaking down medicines, this could be a first step to understanding why people react differently to certain medications. It also sheds light on why we experience cravings and may provide insights into the genetics behind habit formation.