We all wish we knew. We don't.
Certainly, concussion within females is one of the hottest subgenres of concussion research at the present time. We are all looking for answers to that question. We certainly know that females, across many athletic injuries, are at higher risk. This is distressing in terms of what the issue is for females in particular, because the rates in soccer approach those in hockey. I'm sorry, I'm not supposed to complain about the other guy's sport, but our female soccer players have pretty high rates of concussion. Why is that? I think other researchers are working in this field. Certainly my Twitter feed blows up regularly on females and concussions.