Cell phones may cause brain cancer. Last week, the World Health Organization issued a report putting cell phones on the list of carcinogens. The list includes pesticides such as DDT and gasoline engine exhaust. The report, which is based on published studies, came from WHO’s International Agency for Research on Cancer. Though speculation about cell phones’ negative effects on the brain have persisted for years, some scientists are skeptical about WHO’s report, saying published studies don’t conclusively say whether cell phones can cause brain cancer.