Cell phones produce non-ionic electromagnetic radiation. This was once widely believed to be harmless, but that belief was erroneous. It is now known to damage sperm, and potentially to damage cellular metabolism in a way that leads to DNA damage and cancer. Although the effects of non-ionic radiation are less extreme than ionic radiation – which is the sort used for x-rays, and comes from nuclear facilities – regular, long-term exposure is nevertheless unsafe.
It is especially dangerous for children and teenagers to be exposed to cell phone radiation. This is for two reasons. Firstly, exposure at a young age increases their lifetime exposure, and is therefore likely to increase their long term risk of brain or other cancers.
Secondly, while the brain and nervous system are still developing, the effect of radiation is likely to be more pronounced. It has been estimated that talking on a cell phone for 500-1,000 minutes monthly increases the probability of brain cancer by 300%. Since many teenagers equal or exceed this amount, the long term risk for them is grave.
It can be hard to restrain teenagers from using a cell phone, but by keeping it in an anti-radiation phone case the risk of harm is eliminated, or at least greatly reduced. These cases block the radiation from the phone before it reaches the body.