It seems to me that a study was published some time ago that indicated ham radio operators had a higher incidence of leukemia than the general population. Perhaps other hams here on the forum can correct me if my memory is faulty on that.
It also seems to me that the resonant frequency of the average human skull is around the frequencies used for 3G or so.
Right or wrong, good, bad, or indifferent and despite my love of radio as a ham operator, I don't use cell phones (by placing them up to my ear) as much as many do and I probably do more to try to limit my exposures to Wi-fi signals than most.
Having said that, I'll freely acknowledge that my brother, also a ham operator, doesn't approach it as I do.
Peterson