In the spring, 23andMe, a DNA testing firm, was the first company to win approval from the Food and Drug Administration to sell directly to consumers, without a prescription, a genetic test that screens for several diseases, including late-onset Alzheimer’s, Parkinson’s and some rare blood disorders.

Here’s how it works: You pay $199 online for a Health and Ancestry kit. When it arrives, you spit into a tube and mail it back. Two months later, you can view your results in your online account.

Tests like this aren’t new, but in the past you could typically get one only if your doctor ordered it. And often it was to screen you for a specific condition, such as the BRCA genes, which put you at higher risk for breast and ovarian cancer. The results were then shared with a doctor, who interpreted them for you. By contrast, the 23andMe test puts the results in the hands of the consumer.

Should you get one? Before you do, consider your motive. What kind of information are you looking for and what are you going to do with it? After all, some of the diseases for which 23andMe has been authorized to provide genetic reports — Alzheimer’s, for instance — have no cure.

Also keep in mind that having the gene for a certain disease doesn’t mean you’ll get the disease. In the case of Parkinson’s, for example, “direct-to-consumer genetic testing can help to identify who is at risk for developing Parkinson’s but cannot predict who will be diagnosed,” says John Lehr, CEO of the Parkinson’s Foundation.

The same is true of Alzheimer’s. That’s one reason the Alzheimer’s Association discourages genetic testing, says Keith Fargo, director of scientific programs and outreach. “It’s not going to answer the question most people have: Will I get Alzheimer’s or not?”

Nevertheless, some people are “information seekers,” says genetic counselor Susan Hahn. And information can be powerful. It could push some people to adopt healthier habits, a major factor in staying well.

If you choose to get a genetic test for health risks, seek counseling from a genetic specialist or a doctor, who can help you understand your test results. Genetic counseling is not included in 23andMe’s Health and Ancestry kit. But the firm’s website provides resources that help connect customers with counselors.

Nellie S. Huang is a senior associate editor at Kiplinger’s Personal Finance magazine.