“Most negative results were seen for short-term users, below 10 years of use,” she said in an e-mail interview. “It is well known that the latency period for cancer development, and certainly for brain tumor development, is longer. The problem is, of course, that we are dealing with a relatively new technology.”

Besides the recent studies that have found some cause for concern, the controversy over cellphone safety was stoked recently when an Australian neurosurgeon published a paper on the Internet saying phone use “has far broader public health ramifications than asbestos and smoking”.

The doctor, Vini Khurana, analysed data from over 100 studies, concluding that most weren’t long enough to uncover a risk of brain cancer and that children haven’t been adequately studied. His Internet paper and recent appearance on CNN’s “Larry King Live” show rankled some health experts because of his alarming stance.

“The position he took was rather extreme,” says McCormick.

King’s show was followed with a blog posting on cnn.com by the network’s chief medical correspondent, Dr Sanjay Gupta, who also appeared on the show. The item cast doubt on cellphone safety and noted that both Khurana and Dr Keith Black, a neurosurgeon at Cedars-Sinai Medical Center who appeared on King’s show, use hands-free cellphone devices. A spokesperson for Black says he is no longer commenting publicly on potential cellphone hazards.

Says Sadetzki: “I believe that the cellphone technology has a lot of advantages and is here to stay. But we, as a society, need to decide how to use it. The precautionary principle advising the use of simple measures to lower exposure should be adopted and taken seriously.”