SEATTLE - You may not think twice when you make or take a call on your cell phone, but a new report offers some reasons for concern. The International EMF Collective (EMF stands for "electromagnetic fields") report, co-authored by Brian Stein, questions long-awaited research about whether cell phone use can cause brain cancer.

Stein, who also heads a British supermarket chain, says he used his cell regularly for 14 years and then started experiencing problems. He's convinced the phone was to blame.

"If this had happened to you, you would have had no doubt whatsoever what caused it. As soon as I put the cell phone to my head, major pain; as soon as I removed it from my head the pain went away. It was as dramatic and instantaneous as that."

The report questions the 13-country "Interphone" study that is still to be released. Stein says the research techniques in that study are flawed and could skew its findings.

While he is not advocating doing away with cell phones, Stein thinks safer technologies can and should be developed. Cell phone companies have long asserted that the radiation isn't hot enough to cause tissue damage.

Dr. Ronald Herberman with the University of Pittsburgh Cancer Institute says strong evidence points to a link between cell phones and adverse health effects, including cancer, "particularly in people who've been frequent users for more than 10 years. And there is indication that there is more absorption into the brain of the radio frequency radiation in children, as compared to adults."

U.S. Senate hearings on the potential dangers of cell phones are reportedly being planned for next month.

The report is "Cellphones and Brain Tumors, 15 Reasons for Concern: Science, Spin and the Truth Behind Interphone." ("Interphone" is the name of the 13-country study.) It is available at www.radiationresearch.org/pdfs/15reasons.asp.