The higher the frequency of electromagnetic waves the more dangerous to humans they are.
This is true. It is like the difference in the 60hz transformers I use to build ozone units and the high frequency solid state transformers that I tried and kept frying my ozone tubes even though they were lower voltage. I found out that the high frequency really drives how far the energy can penetrate. If we think about it though cordless and other phones keep going up in frequency to allow further reception.