The question might arise every time the cell phone rings: Is this wireless device affecting my health?

For now, science isn't ready to conclude whether radiofrequency energy, or RF, causes health problems, although considerable research to date has found no such link.

But the National Research Council issued a report yesterday outlining a wide range of research it thinks is necessary to answer the question once and for all.

"Perhaps the single most important question concerning the health effects of exposure to RF fields is the possible link between such exposures and cancer risk," the report states.

The NRC report now goes to the Food and Drug Administration to determine what research should be pursued and how it will be funded.

"What we suggest would improve the understanding of what's going on here," said Frank Barnes, University of Colorado professor of electrical engineering and chairman of the committee that completed the report.

The 66-page report does not outline existing research nor offer conclusions about any health effects associated with wireless devices. Based on his own expertise on the topic, Dr. Barnes said research to date is mixed.

"There's a little bit of data that says we should be concerned, and a lot that doesn't see any concern," he said. "So I'm not going to tell people whether they should or should not [use cell phones].

"My observation is, a lot of people are using them, and we haven't seen monster effects," he said. "But maybe it's too early to see effects."

He said life already is full of risks, including driving to the grocery store. So people must decide what level of risk they are willing to take.

But CTIA-The Wireless Association said there already are good studies, including one it funded through the FDA, that found no health concerns.

"We've always been supportive of good science," said Joe Farren, association spokesman. "But when you look at peer-reviewed science published in leading scientific journals, you'll conclude there's no association between the use of wireless devices and health effects."

In August, the National Research Council held a workshop of international experts to identify gaps in research on the biological or health effects humans face from wireless devices.

Its resulting report calls for a wide range of research to determine exactly how RF energy might affect humans, if at all.

Only then can experts make "rational, informed decisions" about the health impact and whether even more studies are needed, it said.

One priority is whether RF causes tumors, the report states.

It calls for epidemiological studies of children, pregnant women and adults involving cancers, including brain cancer, and the impact, if any, on people receiving medium to high occupational RF exposure.

The report says studies to date have mixed results, were limited in scope or had flaws in procedures. It also said cancer studies already under way could help answer the health-risk question and determine whether even more studies are necessary.

In recommending human laboratory studies, the report stressed the importance of determining whether RF affects brain function, blood pressure, sleep, hearing function, cardiac arrhythmia, and cognitive performance -- and whether it causes headaches.

Other research goals include determining precise exposure rates of RF electromagentic fields that children and pregnant women receive from base-station antennae.

New research also should determine whether RF has an impact on the immune, endocrine and central nervous systems and on human genes and cell growth.

In issuing its report, the committee said its goal is to "increase our understanding of the potential adverse effects of RF energy on humans."

From his own perspective, Dr. Barnes said short-term usage of wireless devices reveals no obvious health problems.

"People aren't using phones and dropping dead," he said. "But it's a harder to determine the long-term effects of usage."