The issue isn't risk, but increased levels of risk. "How risk tolerant are we?" is the true question. If we want to go anecdotal, the only concussion I ever suffered was a head to head collision in a basketball game as an 7th grader. Clearly there is increased risk of brain injury from basketball. I also got hit in the mouth with a line drive practicing baseball when I was 13. The only thing that saved my teeth was my new braces. Clearly there is increased risk of brain injury from baseball.
So what it boils down to is how much increased risk involved and acceptable and that is where the debate lies. I'm arguing the increased risk of a boy playing tackle football from ages 10-18 is much less than it used to be and is within an acceptable level on par with other common sports. Some people disagree.
According to
this study, "Among athletes ages 5 to 14, 28 percent of percent of football players, 25 percent of baseball players, 22 percent of soccer players, 15 percent of basketball players, and 12 percent of softball players
were injured while playing their respective sports."