Keep wearing your helmet. Just don't lie about what it's capable of doing.

That's what makes the paper Chasm54 just cited interesting: even given a reading of the literature which is apparently skewed towards accepting that helmets do something besides stopping scrapes and cuts it's seems probable that in Canada widespread helmet use has not decreased concussions, death, and mental impairment.

You can start whining when you get a cop coming up to your daughter and telling her to take her helmet off. Until then it would be prudent for you to zip it up unless you want to be taken for anything other than a troll.