Some researchers at the University of Vermont found some linkages between the genes that cause people to have blue eyes and those that may predispose people towards alcoholism.
Although individual choices and family history go a long ways in creating alcohol dependency, there are some physical differences in the ways that people's bodies actually process the substance that can tip the balance. The study shows that the genes for both of these traits are on the same chromosome, which means they might be linked.
As the story shows, the scientists first noticed correlations in two external features of people in the study: Lighter-colored or blue eyes and alcohol dependency. By itself, of course, that's just a statistical anomaly that can come in any random study. There would be random groupings that might show a high correlation between alcohol dependency and having a certain letter in your last name, for example, because random groupings can wind up doing that randomly.
But being scientists, the researchers decided to see if there was some causation with this correlation or if it was just random. That's when they found that the two genes are on the same chromosome, which is a much stronger connecting factor than random statistical grouping. It's still not causatory, though -- nothing suggests that having blue eyes makes you likelier to be a drunk or that being a drunk makes you likelier to have blue eyes. I imagine most of the news reports on this study, though, will have headlines that are a lot less precise and leave the casual reader with just such an impression.
A much more probable explanation has already been offered, anyway, by researcher P. Townshend: "No one knows what it's like to be the sad man, to be the bad man behind blue eyes."