The ubiquity of WiFi and potential health effects is being debated again. Although all the health studies say no, my mother had some large power line distribution not far from her bedroom and ended up dying from brain cancer. Obviously 0.1 Watt WiFi is not much, but...
http://arstechnica.com/news.ars/post/20080530-santa-fe-wireless-sensitives-fight-hotspot-plan.html