The primary issue being considered as a negative physical effect of cell phone usage relates to the incidence of brain cancer. So far, the scientific community has been unable to say definitively whether cell phones can contribute to brain cancer. Having come into widespread use in Europe during the 1980s and the United States in the 1990s, not enough time has passed for long-term studies to mean much. To date, studies taken as a whole have yielded inconsistent results. When one indicates a slight elevation in risk, another comes along and finds no association. An excellent summary of the work to date done on the topic can be found at Cancer.gov.
Thirteen countries participated in an intensive study (The Interphone Study) coordinated by the International Agency for Research on Cancer. When the final analysis is complete, this should the most far-reaching research done to date.Addiction
Negative effects of cell phones are mostly personal. It's likely you know someone, possibly a teenager, who appears to have had their cell phone grafted to their wrist. It never leaves his hand and is always open for talking and texting. This is no small annoyance. Society's technological toys invite addiction just as serious as alcoholism or drug addiction. For instance, teens and adults alike can drive with their attention split between the road and tapping out that "critical" text, with potentially deadly consequences through inattention.
Read more: http://www.ehow.com/list_6103074_negative-effects-cell-phone.html#ixzz2uGl8jZ54