Mailing your spit to a company so they can tell you vaguely where you came from has been around for a while. (I tried it in college and was dismayed to learn that, as my ruddy peasant complexion has always suggested, I am 95 percent Northwestern European.) But ancestral knowledge is not what’s projected to turn direct-to-consumer (DTC) genetic testing into a $310 million industry by 2022. That boom will come from a major shift in focus from our long-dead relatives to ourselves. For a vial of saliva and a hundred bucks, you can now get detailed reports on how your unique genetic variations may be affecting your sleep, mood, life expectancy, and ability to carry a tune.

I recently took many of these tests. And for someone who balks at saying her Social Security number out loud, I was surprised at how easily I handed over my most personal possession — a detailed map to every cell in my body — to companies I basically knew nothing about. The prospect of being rigorously analyzed as a specimen at the most fundamental level was just too intriguing to pass up. Sure, my lifestyle and health decisions have been rigorously analyzed before — not long ago, I spent a year living with my parents­ — but this wasn’t my mom suggesting I might like to “go for a nice walk.” This was science.

Over 99 percent of my genome is the same as yours; in particular places, though, variations occur. And a subset of those variations has been associated with certain diseases or traits. DTC genetic testing companies make their predictions and recommendations based on a very tiny proportion of that very specific subset. Most of them don’t test your DNA themselves; they send the saliva samples to third-party labs to be translated into the unique sequence of compounds that make up your genetic code.

This information is then sent back to the company, where scientists analyze the data and compare your genetic variations to those that research has connected to different diseases or characteristics. “The information powering all of these companies is in the public domain,” says José Ordovás, the director of the Nutrition and Genomics Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “The distinction comes in how much of this information they decide to use and the type of research that they consider valid.”

Although the recommendations I got weren’t far off from health tips I’ve heard before, I found that I actually followed them.

So far, there is not much oversight of this burgeoning industry. Most of the independent genetics experts I spoke with stressed the distinction between at-home genetics and the technology that doctors and research labs are using. It’s not that these tests are inaccurate — it’s just that they’re usually looking at a narrow group of genes and making predictions based on a single variation. So I chose to take my results like my horoscope: fun to think about, but not exactly gospel.