owen thomas had never been diagnosed with a concussion. >> we were hopeful that this 21-year-old who'd been playing 12 years, that they would show that, you know, you need more than 12 years to get this disease; you need some more... you need real concussions to get this disease. but owen's case kind of opened up a huge, dark world. >> it was like this could happen to anybody. anybody who's playing this game, this could happen, this could be the result. the question is, when does this start? is this a process that starts much earlier in life than we are used to be thinking about? ( marching band playing ) >> narrator: despite the public discussion about its health risks, more kids play football than any other sport-- over a million across the country. a quarter of the boys at shiloh are on the football team. >> it's another great opportunity this week. we get to play the team that's the number one team in the country. >> narrator: last season, shiloh was invited to compete in one of the premier match-ups in high school football... >> the burger king national kickoff classic... >> narra