If you're a woman in midlife, you probably read the recent headlines proclaiming that a new study had discovered a definitive link between the use of menopausal hormone therapy and breast cancer. Scary stuff. But you might also have noticed stories about another study that found that hormone users who do get breast cancer won't die of it. Maybe not so scary. What does this news mean for you? Does it tell you whether it's safe for you to take hormones if your hot flashes are making you crazy? Despite all the hysteria, the truth is that neither study—nor any other single study—can answer that question for an individual woman. But the publicity they prompted illustrates why so many patients are confused.

Here's what you need to know: no single piece of research can ever be 100 percent definitive. Scientific discovery is open-ended, which means that the best studies answer some questions but also raise new ones. And no study, no matter how carefully conducted or designed, can pinpoint your individual risk. That is a task for you and your doctor. When it comes to hormone therapy, for example, the decision should not be based on the latest headline but on your need—whether hot flashes are really making you so miserable you can't function—and your medical history. If you or a close female relative have had breast cancer, that changes your risk. Hormone therapy can also make you more vulnerable to a heart attack or stroke so women with diagnosed cardiovascular disease would probably not be good candidates.

With all the seeming confusion, it's easy to understand why so many midlife women feel like conventional medicine has let them down. For years, hormone therapy was routinely prescribed to prevent heart disease. Then, in 2002, the National Institutes of Health halted a huge study of hormone therapy called the Women's Health Initiative (WHI) because researchers had concluded that taking estrogen and progestin raised the risk of heart attacks, strokes and breast cancer. Since then, many researchers have used the WHI data to paint a more nuanced picture of the risks. That's why you see frequent headlines on the subject.

Medical research is a slow and often messy business. Twenty years ago, much of that mess was hidden from the public. The main forum for studies like these two would have been scientific meetings or peer-reviewed publications like The New England Journal of Medicine, where the audience is trained to understand the incremental nature of research. Your doctor might hear or read about the latest studies; you would not. Doctors were the filters and as a result, most patients took their advice without questioning it.

That has changed dramatically. A major reason is the explosion of medical advertising on television, in print and online. With all these ads, the demand for stories about health and medicine also soared. It's a symbiotic business. In the past, reporters might have waited until a number of studies pointed in one direction to write a kind of summing-up piece. Now, every piece of research—even if it ads only infinitesimally to the base of knowledge—is often trumpeted as the next big thing because of the ravenous demand for such news. "What makes for good science is a healthy dose of skepticism," says Michael Lauer, director of the National Heart, Lung, and Blood Institute's division of prevention and population sciences. "That is also true of scientific reporting in the media. The best advice is to think like a scientist and try to be skeptical."

On the plus side, consumers have access to more health information than ever before. In an era when cost-cutting means you probably have only a limited amount of face time with your doctor, it's good to be better informed. Ideally, you and your doctor will become better partners in managing your health care. The problem is that so much medical "news" is presented without adequate context—and without that necessary skepticism—so it's hard for the average patient to assess its importance.