Edward Kennedy’s brain tumor has everyone debating the safety of cell phones again. But this time around there are some disturbing new studies that suggest all that heat and radiation so close to our brains might not be benign after all. The American Cancer Society and the F.D.A. continue to say there’s not a clear enough link. But last year, the American Journal of Epidemiology published a study from Tel Aviv University showing a 58 percent higher risk of parotid gland tumors among heavy cell phone users. A Swedish analysis last year of 16 studies found the risk of acoustic neuroma and glioma doubled after 10 years of heavy cell phone use. And if that doesn’t convince you to trade in that Bluetooth this surely will: Johnnie Cochran’s neurosurgeon believes the attorney’s tumor was caused by his cell phone and told Larry King last week that he himself uses an earpiece.