According to a landmark study, 99 per cent of NFL players' brains that were donated for research were found to have chronic traumatic encephalopathy (CTE) - a degenerative brain disease linked to repeated head trauma.
And now one researchers is suggesting that popular Aussie contact sports such as rugby league, rugby union and AFL could soon cease to exist.
"We are dealing with human life here. In the next generation or two, mankind won't be playing sports like rugby or football or ice hockey or mixed martial arts," says Doctor Bennet Omalu, speaking to the Brisbane Times.
"It just doesn't make sense to be damaging the brain of a human being. In a game like rugby, in every play there is a blow or impact to the head. The human species evolves, it's part of who we are to change. Society evolves, we move forward."
Dr. Omalu suggests restricting contact sport to over 18s.
"Your brain is 60-80 per cent water, it's a very sensitive and vulnerable organ that floats freely inside your skull. There's nothing holding it down. So every sudden change in motion, the brain jolts around in your skull," he continued.
Former Rugby Union profile Barry "Tizza" Taylor is one of the worst known cases of sports-related CTE. The legendary coach passed away in 2014 from the degenerative brain disease.
Several rugby personalities have now come forward, donating their brains to science once they pass away. This comes after Sydney University released a report that CTE had been found in two former rugby league players