Great cancer risk in presence of GSM base stations (in German):
Austrian research confirms GSM base station health effects:
Non thermal effects:
Brain tumour risk from mobile phone use (WHO study):
DNA damage from phone radiation:
The people who consider this to be a "nocebo" are not being balanced in their assessment. Look at the http://www.psrast.org/mobileng/mobilstarteng.htm website for non corporate funded studies. Neither the government, nor mobile phone companies, have any obvious interest in promoting this (billions in profits, tax revenue, better productivity etc.). Wifi is very similar to mobile phone radiation, except Wifi is much stronger. Some US universities have banned wifi because of its effects on concentration and attention span, and the EU recognises electromagnetic hypersensitivity as a disability. Here's Olle Johansson (neuroscientist at the Karolinska institute, which awards the nobel prize in medicine) talking about it: https://www.youtube.com/watch?v=cczGVhd63pM
Note that major mobile phone manufacturers (e.g. Apple) have started warning customers in their liability statements, not to keep the phone next to them but at least a certain distance away from them.
So don't buy into the "I believe the scientists durrr!!!" argument because science, like everything else in life, is affected at least partially by interests and a majority of non-industry funded (i.e. independent) studies done on this subject have found effects from this kind of radiation, whereas a majority of industry funded studies have found no effect, sometimes through tricks and manipulations. E.g. The Interphone study, and then the BMJ study based upon it, excluded the tumour rate of business users, who have used mobile phones for longest and most extensively. Then they found, unsurprisingly, no link between "heavy" use, in their much shrunken sample set excluding heavy users, and health problems. Here's an article which mentions the difference between industry and independent studies: http://www.digitaltrends.com/mobile/can-cell-phones-cause-brain-cancer/
As for whether people can detect wifi or not, why is that relevant? It seems totally irrelevant, except to dismiss the small minority of people who can genuinely detect these things (if indeed it is the case that they can). The purpose of this line of argument seems to be to pathologise those who have real concerns about electromagnetic radiation as crazies who can predict the future by reading tarot cards. People cannot easily distinguish if they have brain tumours, but they certainly have them! Even so, here's another study (double blind) finding a change in heart rate for people with and without the use of cordless phones (which use similar radio-waves): http://www.powerwatch.org.uk/news/20101022-cordless-heart.asp study is: 2010 M.Havas, et al: Microwave Radiation Affects Autonomic Nervous System, Eu J Oncology Library Vol.5
As everything else in life, be truly skeptical and pursue things with moderation. I own, and use when necessary, an expensive and very capable smartphone, but I only make calls on it if I have to and put it in flight mode except when I need to use it. Circumstances might be different for other people but certain communications clients allow computer messaging (e.g. Viber or Whatsapp) and if your computer is connected to your router with a wire, you're getting around the need for wireless access. Perhaps Windows 10 mobile will integrate this into the default messaging service. It isn't easy to live a wired life but it is more secure and more safe, and the inconvenience is relatively minor. I know many people are tied into the Apple ecosystem, some platforms of which do not have wired internet access. Perhaps it is time to make a change, or buy the wired adapter.
Certainly the idea of the house running on wireless electricity with a gigantic wall power plate is ridiculous for this reason, but one doesn't have to give up technology to live safely - just use it carefully, and in moderation.