You can chose a different TSA agent. Going to another doctor won't change the fact that, to diagnose certain problems, he/she may need to touch your testicals.
However many people, especially men, do not allow embarrassing and painful tests done to them unless they're scared. They literally choose increased chance of death over those invasive exams.
I feel people should have the same right at the airline gate (aka flights w/o gropesearch/poronoscans vs flights with being offered)
