"My sense of it is, we're going to see a drop in participation," Hallenbeck said.
Hoping to ease those concerns, USA Football — a national organization founded by the NFL and the NFL Players Association — has put safety measures in place in recent years for the youth leagues that have joined its membership. USA Football-affiliated coaches must take a training class and pass a test, then follow specific instructions that include proper equipment fitting, an age-specific approach to teaching tackling and other techniques, and limits on contact in practice.
This fall, USA Football will launch what Hallenbeck believes is the first comprehensive study on injuries in youth football.
"Clearly, there's a concern, and we have been proactive on that for five or six years," Hallenbeck said.
Dr. Shayne Fehr, a pediatric/adolescent concussion specialist at Children's Hospital of Wisconsin, said more parents are expressing safety concerns to him.
"I had a patient this past week, he came in with his second concussion," Fehr said. "I believe he was about 14 years old, and his mother said — before he even got a chance to talk — that he's done with football."
Yet Fehr also said such dramatic declarations are rare.
"You have to remember that a lot of times, these families have grown up with sports such as football," Fehr said.
Former NFL quarterback Kurt Warner caused a stir recently when he said he worried about his own children playing football, but he's not the only ex-pro with reservations. For ex-NFL safety Matt Bowen, there aren't easy answers when it comes to balancing safety concerns against the positive things kids can learn from football.
"But I've had this conversation with my wife quite a bit, and I know in our house, our boys aren't going to play youth football," Bowen said. "My wife's already taken care of that. That's just not going to happen."
Bowen, who now writes columns for the Chicago Tribune and the nationalfootballpost.com website, gets a lot of questions from fellow fathers.
"I tell them that I love the game," Bowen said. "I respect everything I learned from the NFL, and in college and in high school. I don't think there's a better sport out there in terms of teamwork. I really don't, in terms of learning how to deal with some adversity that you deal with in real life. But I also tell them I got beat up a lot, had a lot of injuries. People ask about concussions all the time. 'What do you think? What's your stance on it?' A lot of times I just change the discussion. You're out drinking beer with some dads and they ask you, you talk about it a little bit. Yeah, I think it's violent. I think it's violent and I think it's made for young men, not little boys."
Kia LaBracke experienced that violence firsthand when her son, Nico, sustained a concussion from a big hit he took while returning a punt in a freshman football game in Oconomowoc, Wis. last fall. It took him months for him to recover and return to school full-time, leaving LaBracke and her husband, John, to make a difficult decision: They weren't going to let him play again.
"We knew it was going to be very tough," LaBracke said. "Because he's very dedicated to the sport, he's a very hard worker. This was his thing. A lot of his identity, who he was and who he is, was tied up in that."
LaBracke, who had a working knowledge of concussion issues through her job as the executive director of the Wisconsin chapter of the American Academy of Pediatrics, said her son didn't take the decision well.
"On an intellectual level, of course he understands," LaBracke said. "He would never say that, but of course he understands it. But I still don't think he's quite let go of the feeling that this is really unjust."
Now Nico's younger brother, Jack, is playing.
"But we've told him flat-out, we don't know how long this is going to last," LaBracke said. "We may cut this off at any point. And he understands it, because he watched what his brother went through. He was there when Nico came home and didn't know who his own brother was. I don't think he would be surprised if we pulled the plug at any point."