As I kid I visited a broadcast transmitter up on the mountains with its own hydropower generator. There was staff on-site who had worked there for years. How long do you think is needed to compare working 8 hours a day at a 500kW radio transmitter broadcasting all the time vs. holding a smartphone or using wifi with only a few hundred milliwatts? (mW values at https://en.wikipedia.org/wiki/DBm .) Again, there's enough RF power from the transmitter to make a florescent bulb glow.

The biophysics would pretty incredible, even unbelievable, for a certain geometry and frequency to make a difference. Microwaves are a few centimeters long, and longer than sperm or even the testes. What mechanism could make them so specific to frequency?

But putting that aside, different countries use different frequencies (https://en.wikipedia.org/wiki/Cellular_frequencies says "Many GSM phones support three bands (900/1,800/1,900 MHz or 850/1,800/1,900 MHz) or four bands (850/900/1,800/1,900 MHz), and are usually referred to as tri-band and quad-band phones, or world phones; with such a phone one can travel internationally and use the same handset.")

If there were a significant problem with one specific frequency then it would appear in an epidemiology comparison.

Fundamentally though, your line of questioning can have no end. What if it only affects people with one of about 30 point mutations? What if it's only for those who have a diet with an excess of selenium? What if it's only at a certain power level? What if ... what if .. what if?

Each of these is hard to test, and given the difficulty of the biophysics it's hard to justify spending a lot of money when other options, including "More refined sugar?" and "Less physical activity?", seem more likely.