manufacturers say the technology is safe, but many scientists say the opposite, in between the need for communication that we often have to use a cell phone.
devices are not all alike and not all have the same level of risk, one way to minimize this risk is to choose a model with low radiation.
There is an American NGO with a large database about it. I recommend you check there before buying a new computer.
http://www.ewg.org/cellphone-radiation/
It is also interesting to know the practices for a safer use of the telephone or reduce radiation exposure
http://www.ewg.org/cellphoneradiation/8-Safety-Tips
A translation of its own:
1. BUY LOW RADIATION CELL
Find the model and manufacturer in the EWG database: www.ewg.org / cellphoneradiation / Get-A-Safer-Phone . (The model is usually under the battery.) Consider if necessary, replace the computer with one that emits the lowest level of radiation as possible and have the performance required.
2. HANDS FREE USE HEADPHONES OR
These devices emit less radiation than the telephone. Choose wired or WIRELESS according to convenience or chance. (Opinions are divided as to which option is safer, but it is less harmful): www.ewg.org / cellphoneradiation / Get-a-Headset . Some headsets emit continuous low-level radiation, so do not use it permanently, only to place or answer a call.
Using the headset or speaker phone is the safest way.
3. Listen more, talk less
The equipment emits radiation when you write or speak, but not receive calls or messages
4. SEPARATE TELEPHONE HAVE THE BODY
Specifically torso or heard speaking. Is more convenient to have it on a belt or pocket and use in device handsfree.
5. SMS INSTEAD CHOOSE TO TALK
message system uses less power and therefore emits less radiation to send voice messages to send.
6. LOW SIGNAL? PHONE AWAY! The lower
phone signal greater the emission of radiation used to make a connection. It is convenient to make and receive calls in high-signal conditions.
7. LIMITING THE USE OF CELL IN CHILDREN (I prefer to avoid it altogether)
a child's brain absorbs twice the radiation than an adult, so if it is not essential (emergency), would be preferable for children to NO cell use.
8. AVOID RADIATION SHIELDS
protectors keypad antenna or reduce the quality of connection and forces the computer to transmit at higher power generating higher levels of radiation.
information created or collected by neighboring barracks, fighting for quality of life 
