Anecdote: I avoided all these things and more out of pure hypochondria for decades, and I impregnated my wife the two times we didn't use some form of birth control. I even have a sort of tic I integrated where I pull my testicles out from between my legs when they get constricted, and hadn't remembered why I started doing that until you reminded me that I read something about heat being bad for sperm in the 90s.