“Ten years ago a group in Denmark published a beautiful epidemiological study of cell phones and brain cancer in the Journal of the National Cancer Institute: Johansen C.Boice JD Jr, McLaughlin JK, Olsen JH. Cellular telephones and cancer a nationwide Cohort study in Denmark. J Natl Cancer Inst 2001;93:2037. The study was based entirely on existing public records: the Danish Cancer Registry, mobile phone charges, death records, subscriptions, etc. There was no correlation between cell phone use and the incidence of brain cancer. It was nice to have that fact confirmed, but it was not a surprise. I was invited to write an editorial on how scientists should respond to the cell phone/brain cancer question, for the same issue of JNCI JNCI, Vol. 93, No. 3, 166-167, February 7, 2001. Cancer agents act by creating mutant strands of DNA. In the case of electromagnetic radiation, there is a sharp threshold for this process at the extreme blue end of the visible spectrum. Albert Einstein explained this with the photoelectric effect in 1905, for which he received the Nobel Prize in 1921. Cell phones operate at a frequency about 1 million times lower than the ultraviolet threshold and hence cannot be a cause of cancer. It’s not the intensity of radiation that makes it a cancer agent, but the frequency. “”