If a car manufacturer suddenly told you fenders were useless, you might raise an eyebrow.
If a sporting goods designer told hockey goalies that their serial-killer masks didn't prevent concussions, there might ensue a fight.
So when a neurosurgeon offers that cycle helmets are pointless, you might imagine that the more bellicose spoke of the cycling fraternity might wonder if he's been in the pub all day.
However, Dr. Henry Marsh, a neurosurgeon at St. George's Hospital in London, believes many cycling helmets are simply "too flimsy."
As the Telegraph reports, Marsh was speaking at the Hay Literary Festival. There, he threw caution to an erudite wind by saying: "I ride a bike and I never wear a helmet. In the countries where bike helmets are compulsory there has been no reduction in bike injuries whatsoever."
There are surely those who would differ. All over the world, parents equip their children with bike helmets, in the sure belief that those helmets will protect little heads.
Marsh, however, believes science doesn't prove this.
Worse, he pointed to research from the UK's University of Bath that said the mere presence of cyclists wearing helmets makes car drivers feel they are safer.
Logic then propels them to drive 3 inches closer to these cyclists, hence enhancing the possibility of accidents.
That research, conducted in 2006 by a psychologist who had himself been hit by a truck and a car while cycling, insisted that drivers became more careless around helmeted cyclists.
However, it did acknowledge that helmets were useful for children, who are more likely to be involved in low-speed accidents.
Campaigners for road safety have wanted to knock Marsh's suggestions on the head. Angela Lee, chief executive of the Bicycle Helmet Initiative told the Telegraph: "It would be a travesty if somebody takes their helmet off because of this. It is such a negligent thing to say for a person in that position."
Not everyone agrees. Michael Cavenett of the London Cycling Campaign countered: "I wouldn't say what this doctor has said is particularly controversial. People have been casting doubt on the effectiveness of helmets for 20 years."
For Cavenett, it is far more the design of roads and junctions which puts cyclists in danger.
Marsh isn't alone in suggesting bike helmets shouldn't be worn. In a 2010 Tedx Talk (video above) Mikael Colville-Andersen, cycling ambassador for Copenhagen, insisted that some research found that cycle helmets actually cause more brain damage.
Moreover, he described society's obsession with safety equipment as "almost pornographic." Why, he wondered, don't pedestrians wear helmets, as they suffer more brain damage than cyclists?
For him, riding without a helmet is also a symbol of the livable city. The problem, as he sees it, is drivers, not cyclists. What would happen, he mused, if drivers were forced to wear helmets? That would surely save lives. It would also destroy car sales.
He believes that some of the biggest proponents of cycle helmets are the car industry and the auto insurance industry, as the more laws there are insisting on cycle helmets, the fewer bikes are sold.
Marsh, for his part, declared that instead of a helmet he wears a cowboy hat.
Perhaps there are those who believe that safety should move in another direction. Is there any reason why cyclists shouldn't be forced the wear the same crash helmets those on motorbikes do?
True, it might clash aesthetically with the tight outfits advertising Italian cheese that so many cyclists seem to favor (at least in my area).
But if crash helmets are deemed to be effective, why not use them for all two-wheelers?
Or would cars drive even closer to crash-helmeted cyclists?