This is why I said in my long post above thst helmets and concussions are a very misunderstood topic. I have been involved in many concussion discussions with medical professionals in my long capacity in womens/girls lacrosse and none of those medical professionals, who are actually in related medical fields, say that helmets prevent concussions. One can easily research the topic by googling helmets and concussions. Girls lacrosse is fifth on the list of sports sustasining concussions behind such helmeted sports as footbll (by far the most consussed sport), ice hockey, and boys lacrosse. Girls Soccer is third on the list. Goaltenders are the most concussed players on a girls lacrosse field because the force of the balls impact when shot into the helmet causes the brain to basically rattle against the skull. It is why there is a rule in girls lacrosse, which should be called more often, that hitting a goalie in the head with a shot is a major foul.
Here is the breakdown of sport concussions:
The below numbers indicate the amount of sports concussions taking place per 100,000 athletic exposures. An athletic exposure is defined as one athlete participating in one organized high school athletic practice or competition, regardless of the amount of time played.

Football: 64 -76.8
Boys' ice hockey: 54
Girl's soccer: 33
Boys' lacrosse: 40 - 46.6
Girls' lacrosse: 31 - 35
Boys' wrestling: 22 - 23.9
Girls' field hockey: 22 - 24.9
Boys' soccer: 19 - 19.2
Girls' basketball: 18.6 - 21
Girls' softball: 16 - 16.3
Boys' basketball: 16 - 21.2
Cheerleading: 11.5 to 14
Girls' gymnastics: 7
Girls' volleyball: 6 - 8.6
Boys' baseball: Between 4.6 - 5


Again all of this information can be easily looked up. Statisticlly concussions have dropped in girls lacrosse the last two years due to an emphasis on preventing dangerous checking, slashing, and checks to the head. Basically trying to keep the stick away from the head. However concussions still occur and no player, parent, coach, or official wants to see a player get a concussion. There are many sports related concussion studies going on these days to prevent concussions. We all hope they can shed more light on the problem, but putting girls in helmets, or soft head gear, is not the answer since any hard impact either by a stick or a ball will still cause the brain to "rattle". This is why people get concussions when they are rear ended in car accidents. It is the "whiplash" of the brain bouncing off the skull that does it. It is no different in sports, including girls lacrosse, the whiplash of an impact causes the concussion. Helmets do not stop this whiplash affect and just do not prevent concussions. It is an unfortunate medical and scientific fact.