The Netherlands has achieved the safest conditions for cycling in the world by making the environment safe. This is in contrast to other nations which have ignored the importance of the environment and legislated or promoted helmets in an attempt to improve the safety of children. None of those attempts has succeeded and many of them have resulted in fewer people cycling.
Nevertheless, some Dutch "experts" also promote helmets, taking their cue from countries where almost no children cycle. Dutch cyclists are already safe and there is nothing to gain from promoting helmets here
This is particularly a problem in Zeeland in the South West of the country. We covered this on the blog back in 2010 but sadly they're still at it this year. Nothing good will come from this. Quite apart from the well documented decline in cycling in countries like Australia where helmets were made compulsory, the twenty year decline in Denmark has correlated with their helmet promotion.