Victoria Grove wanted to find out if she was destined to develop the form of emphysema that ran in her family, but she did not want to ask her doctor for the DNA test that would tell her.

She worried that she might not be able to get health insurance, or even a job, if a genetic predisposition showed up in her medical records, especially since treatment for the condition, Alpha-1 anti-trypsin deficiency, could cost more than $100,000 a year. Instead, Grove sought out a service that sent a test kit to her home and returned the results directly to her.

Nor did she tell her doctor when the test revealed that she was virtually certain to get it. Knowing that she could sustain permanent lung damage without immediate treatment for her bouts of pneumonia, she made sure to visit her clinic at the first sign of infection.

But then came the day when the nurse who listened to her lungs decided she just had a cold. Grove begged for a chest X-ray. The nurse did not think it was necessary.

"It was just an ongoing battle with myself," recalled Grove, 59, of Woodbury, Minn. "Should I tell them now or wait till I'm sicker?"

The first, much-anticipated benefits of personalized medicine are being lost or diluted for many Americans who are too afraid that genetic information may be used against them to take advantage of its growing availability.

In some cases, doctors say, patients who could make more informed health-care decisions if they learned whether they had inherited an elevated risk of diseases like breast and colon cancer refuse to do so because of the potentially dire economic consequences.

Others enter a kind of genetic underground, spending hundreds or thousands of dollars of their own money for DNA tests that an insurer would otherwise cover, so as to avoid scrutiny. Those who do find out they are likely or certain to develop a particular genetic condition often beg doctors not to mention it in their records.

Some, like Grove, try to manage their own care without confiding in medical professionals. And even doctors who recommend DNA testing to their patients warn them that they could face genetic discrimination from employers or insurers.

Such discrimination appears to be rare; even proponents of federal legislation that would outlaw it can cite few examples of it. But thousands of people accustomed to a health insurance system in which known risks carry financial penalties are drawing their own conclusions about how a genetic predisposition to disease is likely to be regarded.

As a result, the ability to more effectively prevent and treat genetic disease is faltering even as the means to identify the health risks people are born with are improving.