Dr Keith Hopcroft, a general practitioner in the southeastern county of Essex, has opined that self-examination of the testicles to detect early signs of cancer are a waste of time and possibly harmful.
Singer Robbie Williams and the Leicester Tigers rugby team are among those who have lent their names to a campaign for men to be "testicle aware," just as women are encouraged to look for dangerous lumps in their breasts.
But in a personal view published in Thursday's BMJ, Hopcroft lashes the invitation for a man to "grope his gonads or caress his crown jewels" as "well-meaning whimsy, with the potential to do harm."
"There is no good evidence that routine testicular self-examination is of any benefit," he writes.
"The chances of discovering something significant from routine self-examination of the testicles are minuscule. At least 50,000 men would need to examine themselves for 10 years to prevent one death."
Hopcroft says the "testicle aware" campaign is based on the notion that this form of cancer is a silent killer, with no symptoms of pain.
The campaigners argue men should look for painless swelling that, they say, is a possible sign of cancer.
But, argues Hopcroft, at least half of patients with testicular cancer usually experience pain.
The real question is teaching men to be aware of this symptom and act on it swiftly, rather than "turning the nation's blokes into ball-watching neurotics," he says
Self-examination may turn up benign swellings such as epididymal cysts that are harmless but may cause the man crippling anxiety, he adds.