CNNW Sanjay Gupta MD January 22, 2012
repeated blows to the head, the kind that you get on a football field can have lasting reprecussions. especially for young people. some states are writing new laws. in fact, one just took effect this month here in california. any player on a high school or middle school team who gets a concussion must be cleared by a trainer or doctor before going back on the field. even then, though, the risk is hard to gauge. you can't really see damage to the brain unless you actually look inside. of course, by then it's too late. >> reporter: football is a violent game, full of big hits. what are...
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