My son was a goalkeeper in soccer, and he luckily never had much head trauma. He never had any concussions or anything. I really wanted him to play football, but now I'm thankful he didn't.

The relationship between concussions and the asserted clinical symptoms of C.T.E. remains unknown.

You're not going to eliminate concussions. Anytime you hit your head, you have a chance of getting a concussion, in any sport, too. I think we have to learn more about it. Part of it is rules, part of it is equipment, part of it is medical studies, knowing more about the brain.