I like to plan ahead; that much I knew about myself before I plunged into exploring my genetic code. I’m a healthy 28-year-old woman, but some nasty diseases run in my family: coronary heart disease, rheumatoid arthritis, Alzheimer’s and breast cancer.

So I decided to read the tea leaves of my DNA. I reasoned that it was worth learning painful information if it might help me avert future illness.

Like others, I turned to genetic testing, but I wondered if I could trust the nascent field to give me reliable results. In recent years, a handful of studies have found substantial variations in the risks for common diseases predicted by direct-to-consumer companies.

I set out to test the tests: Could three of them agree on me?

The answers were eye-opening — and I received them just as one of the companies, 23andMe, received a stern warning from the Food and Drug Administration over concerns about the accuracy of its product. At a time when the future of such companies hangs in the balance, their ability to deliver standardized results remains dubious, with far-reaching implications for consumers.