With increased focus on the dangers of brain injuries in kids, Canadian and American pediatricians are banding together to warn of yet another sport that endangers kids and teens: boxing.

Amateur boxing has long been a popular sport in both countries and many boxing-title holders say they began training when they were still in elementary school. But the Canadian Paediatric Society and the American Academy of Pediatrics say children and teen athletes should not be allowed into the ring at all until after age 18, to protect their brains from injury.

"Because of the risk of head and facial injuries, the American Academy of Pediatrics and the Canadian Paediatric Society oppose boxing as a sport for children and adolescents," the groups write in a joint position paper issued Monday.

"These organizations recommend that physicians vigorously oppose boxing in youth and encourage patients to participate in alternative sports in which intentional head blows are not central to the sport."

Dr. Claire LeBlanc, co-author of the new position statement and chair of the CPS Healthy Active Living and Sports Medicine Committee, notes in a press release that while most sports have some risk of injury, boxing is especially dangerous.

She says that's because athletes are rewarded for deliberate hits to their opponent's head.

The groups note that children's brains are more vulnerable to concussion, and recovery takes longer than it does for adults.

"Though amateur boxers wear safety gear, there is no evidence to show that head guards actually reduce the incidence of concussions," the groups say.

The CPS and AAP are urging pediatricians and other health professionals to strongly discourage their patients from participating in boxing.

The warning comes as evidence mounts that repeated head injuries and concussions can lead to a degenerative brain condition called chronic traumatic encephalopathy. The condition causes permanent changes to the brain and leads to personality changes and symptoms similar to dementia.

The condition has been noted among boxers for decades and was once called "dementia pugilistica" because of its prevalence among professional boxers.

According to Boxing Canada, the organization representing amateur boxers, the minimum age to fight in a boxing competition is 11. About 2,000 kids between the ages of 11 and 16 are registered to compete, its records show. About a quarter are girls.

Boxing enthusiasts insist the sport is no more dangerous than other sports that can lead to head injuries, such as hockey, football, skiing or other martial arts.

Dr. David Venturi, the medical advisor to Boxing Ontario, says amateur boxing is "an extremely regulated combative sport."

"Injuries do occur in boxing as in any other sport, but significant head injuries are a rare event in amateur boxing," he said in an email to CTV News.

"Boxing Ontario executives, coaches, chief officials, referees and ringside physicians work diligently together to protect their athletes from significant injury by watching every punch thrown during every fight. These experienced eyes at any time will stop a fight," he said.

In comments made to The Canadian Press, Robert Crete, the executive director of Boxing Canada, notes that amateur boxers spend the bulk of their time punching bags, not each other.

"It's not like playing hockey, where every weekend, the kid is competing," he told CP. "If they compete twice a year, it's considered very often."

The CPS and AAP acknowledge that the overall risk of injury in amateur boxing seems to be lower than in some other collision sports such as football, hockey, wrestling, and soccer.

"However, unlike these other collision sports, boxing encourages and rewards direct blows to the head and face," they note in their paper.

The pediatricians' paper says it's unclear how many children and teens get injured while boxing, since few studies separate data by age group.

But they note that data has been collected by the Canadian Hospitals Injury Reporting and Prevention Program, which collects data from 15 hospitals across the country, including 10 children's hospitals. That database found some 273 boxers reported injuries between 1990 and 2007 and among them, nearly 70 per cent were 18 and under.

Most of those injuries occurred during sparring or competitions.

The Canadian Medical Association has pushed to make boxing off-limits to youth and even advocates that the sport be banned entirely. The American Medical Association recommends that until all boxing is banned, head blows should be prohibited.

Peter Wylie, a former boxer and coach who has trained such notable Canadian boxers as Shawn O'Sullivan, Johnny Kalbhenn and John Raftery, says boxing is not only an excellent form of exercise, it's also one of the few sports readily available to underprivileged youth.

"Boxing clubs and boxing youth programs are typically located and function in inner-city communities, where teenagers in the critical 11-to-18-years age range frequently come from low-income and single-parent households, often lack proper guidance and are therefore at high risk of becoming involved in gang activities," he said in a statement to CTV News.

He says boxing builds self-confidence, helps to channel aggression into a constructive outlet, and helps to develop a respect for rules, discipline and good health.

"Therefore, the function of youth boxing cannot be narrowly viewed only from the purely sport-related technical skills, but must be evaluated also from its social community building role," he says.