Because of this physical law, even if holding a Wi-Fi router directly against your forehead was very dangerous (and, we assure you, it is not) working in your home office 45 feet away from the Wi-Fi router would not be dangerous simply because the microwave radiation of the already minuscule 1 watt Wi-Fi router would have radically decreased in intensity. When you factor in that the Wi-Fi radiation is already harmless, you see that there is no situation in which the Wi-Fi signal from your router, your laptop, your media center, or any other Wi-Fi device in your home could possibly hurt you.
c) and before you raise the argument that visible light is itself electromagnetic radiation, with even shorter wavelengths than microwaves, electromagnetic radiation within the visible light range does not penetrate living cells and other molecular materials as X-Rays (ionising radiation) or microwaves (non-ioninsing radiation) do. Practically all visible light is reflected by our bodies, and therefore it’s energy is not absorbed by our cells and is therefore harmless.
This is an animal experimental study, which was conducted in the Department of Anatomical Sciences, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, IRAN, from June to August 2014. Three-month-old male Wistar rats (n=27) were exposed to the 2.45 GHz radiation in a chamber with two Wi-Fi antennas on opposite walls. Animals were divided into the three following groups: I. control group (n=9) including healthy animals without any exposure to the antenna, II. 1-hour group (n=9) exposed to the 2.45 GHz Wi-Fi radiation for 1 hour per day during two months and III.7-hour group (n=9) exposed to the 2.45 GHz Wi-Fi radiation for 7 hours per day during 2 months. Sperm parameters, caspase-3 concentrations, histomorphometric changes of testis in addition to the apoptotic indexes were evaluated in the exposed and control animals.
The only consistently recognized biological effect of radiofrequency radiation in humans is heating. The ability of microwave ovens to heat food is one example of this effect of radiofrequency radiation. Radiofrequency exposure from cell phone use does cause heating to the area of the body where a cell phone or other device is held (e.g., the ear and head). However, it is not sufficient to measurably increase body temperature. There are no other clearly established effects on the human body from radiofrequency radiation.
Radiofrequency radiation from cell phones is non-ionizing and is not powerful enough to cause cancer. Ionizing radiation, including x-rays and ultraviolet light, produces molecules called ions that have either too many or too few electrons. Ions are known to damage DNA and cause cancer. Cell phone radiation, like radio, TV, and visible light radiation, is non-ionizing and lacks sufficient energy to add or remove electrons from molecules, and therefore it cannot ionize and cause cancer.  According to the authors of a 2005 peer-reviewed study of 3.7 million Swedish residents, a "biologic mechanism that could explain any possible carcinogenic effect from radiofrequency radiation has not been identified." 
This study elucidates the effect of short (15 days) and long-term (30 and 60 days) low level 2.45 GHz MW radiation induced local stress on the hippocampal spatial memory formation pathway in adult male mice. Researchers observed that 2.45 GHz MW irradiated mice showed slow learning and significantly increased number of working and reference memory errors in RAM task. Further, 2.45 GHz MW radiation exposure increases serum corticosterone level and the expression of CRH, CRH-R1 and i-NOS, while the expression of iGluRs, n-NOS, PSD-95, PKCε, PKA, ERK-p-ERK, CREB and p-CREB decreases in above mentioned hippocampal subregions in a duration dependent manner. “Our findings led us to conclude that 2.45 GHz MW radiation exposure induced local stress suppresses signaling mechanism(s) of hippocampal memory formation.”
My phone is a very large concentration of value in an easy-to-lose, easy-to-break package that I’m constantly waving around recklessly. The next time you plop your phone down on a bar, which is a dark place buzzing with dizzy people holding containers full of liquid, remember that what you’re really doing is placing $600 to $1,000 in a situation in which it might instantly vaporize.