Every now and again a story pops up in which scientists question just how healthy those mobile phones we suddenly seem to be addicted to really are. So do cell phones really cause cancer? The answer is pretty much the same as it's always been. Anything in excess is probably not good for a number of reasons. Cell phones, besides being a contributing factor to car accidents are also possibly a mild carcinogen. Although studies are ongoing, the IARC (International Agency for Research on Cancer) does categorize the device as "possibly carcinogenic".
While that's smack in the middle of their threat scale, it's still entry level and somewhat vague since the previous are "not classifiable as to its carcinogenicity to humans" and "probably not carcinogenic to humans". The current research at Tel Aviv University involves measuring "oxidative stress" levels in saliva of individuals classified as heavy users. The original train of thought being that cell phones are placed close to the users salivary gland so the saliva would indicate if anything out of the ordinary was happening. In fact oxidative stress levels were higher in heavy users, which is important because that leads to cell damage, including DNA, which can result in cancer causing errors.
Despite the findings I think it's safe to say we all know a few people who could stand to cut back on the cell phone use. You can check out the full article at eurekalert.org