The Australian study is very biased. Seriously, how many people would stop riding a bike just because they had to wear a helmet. That simply does not make sense.
Why does it not make sense? Most cyclists do not wear helmets. They could, but clearly they do not want to. Given that people do not want to wear helmets, obviously some of these number would further choose not to cycle.
It's not reasonable to assume that all cyclists are so passionately committed to the cause that they would continue cycling regardless of legal changes.
It was reported in the New Zealand Medical Journal (NZ also has a helmet law), that cycle injury rates increased as a result of the law, and cycling fell by a half. journal.nzma.org.nz/journal/abstract.php?id=5046
The same results occur everywhere these stupid laws are introduced - fewer people cycle, and as a result cycling becomes increasing marginalised and unsafe.
I think if people had to wear parachutes to go on an aeroplane flight, fewer people would fly. Same thing with cycle helmets. They present the message - 'this is a dangerous activity, requiring specialist safety equipment'. That is very off-putting, and it's no coincidence that countries where cycling is seen as every day and normal, no different from walking down the street (cycling is safer than walking, on a per distance basis), that helmet wearing is rare.
I will no more force my children to wear helmets to cycle than to walk or go in the car.