"Wi-Fi" covers at least two different frequencies - is the effect observable at both?
And the more we have electromagnetic waves in our environment because of the spreading of the technology, the later we die because medicine and healthcare move faster than the putative harm. What is certain, is that whatever the harm electromagnetic waves cause, it can't be huge like silicosis or asbestos, because we just don't see it in the statistics while intently staring at it, it has to be weak.