Health Canada is very clear on this issue:
"Current scientific evidence supports the assertion that RF energy emissions from Wi-Fi devices are not harmful."
Wifi signals can be found in your home, neighbourhood, schools, coffee shops, malls, and city centres to name a few. RF energy coming from Wi-Fi devices is similar to that emitted from commonly used household products such as cordless phones, video game controllers, remote controls for garage door openers, and baby monitors. These devices have been used in consumer markets for years Based on current scientific evidence, Health Canada has determined that low-level exposure to radiofrequency (RF) energy from Wi-Fi equipment is not dangerous to the public. This conclusion is consistent with the findings of other international bodies including the World Health Organization, International Commission on Non-Ionizing Radiation Protection and the Instiute of Electrical and Electronics Engineers.
Health Canada's position is that no precautionary measures are needed. Wi-Fi exposure levels are typically well below Canadian and international exposure limits, and there is no convincing evidence that they are a health hazard.
The information from this post and much more can be found at: