Cell phone usage has increased rapidly in the last ten years. In 2000, there were 110 million cell phone users and today there are 303 million just in the United States and five billion globally, according to the National Cancer Institute. Cell phones release electromagnetic energy, which is a form of very low radiation that is absorbed in the tissues next to where the phone is held.
A cell phone user’s level of exposure to electromagnetic radiation depends on several factors which include the number and duration of calls, amount of cell phone traffic at a given time, distance to the nearest base station, size of the handset, and whether or not a hands-free set is used. The main worry of electromagnetic radiation is heating, which occurs in a microwave, but not in cell phone usage. The amount of cell phone use is not sufficient enough to cause heating of the body.
The American Cancer Society has concluded that most studies have found no association between cell phone use and development of tumors. However, the studies to date have been limited to the length of follow-up, changing patterns in cell phone technology, and methods of measuring cell phone use. According to CNN Health’s “More muddy water on cell phone use, kids' brain cancer risk” a study defined a group of teenagers that are regular cell phone users as those who use their phone once a week for six months. In this case, the teens that use cell phones regularly are at no greater risk of brain cancer than non-users. In terms of a typical teen that uses their phone close to five times a day, the answer is less clear.