Re: cancer
there is no conclusive evidence either way, but better be safe. I worked on issues relating to cellphone and even other transmissions on human health back in 2003-2004 timeframe and worked quite closely with FCC and some manufacturers at that time.
So the evidence form either side can either make you very nonchalant about it or very nervous, so be safe just to be sure. In the meantime what you can do is figure out what the Specific Absorption Rate )SAR) is for your phone, by FCC regulations manufacturers have to note it but the industry does not want to use SAR levels as an advertising pitch so only way u can find it is on manfuacturer website, or in the phone manual. Sar basically measures the quantity of radiofrequency absorbed by the human body .
The max SAR levals are
less than 1.6W/kg in US and Canada
2W/kg in EU
I forget the other differences between US and EU, but it had somethign to do with the amount of body mass that was considered in that w/kg calculation. EU looked at total body I believe while US looked at just the head and part of upper body.
and just to clarify I am not an engineer or an EMC expert. I worked to develop SAR testing business (along with other wireless technologies e.g. wimax, wifi, bluetooth) in that time so had to be up to speed on industry issues.