<P> Robert Cantu, a Professor of Neurology and Neurosurgery and Co-Founder of the CTE Center at the Boston University School of Medicine, believes that children under 14 should not play tackle football . Their brains are not fully developed, and myelin (nerve cell insulation) is at greater risk in shear when the brain is young . Myelination is completed at about 15 years of age . Children also have larger heads relative to their body size and weaker necks . </P> <P> Chronic traumatic encephalopathy (CTE) is caused by repeated brain trauma, such as concussions and blows to the head that do not produce concussions . It has been found in football players who had played for only a few years, including some who only played at the high school level . </P> <P> An NFL - funded study reported that high school football players suffered 11.2 concussions per 10,000 games or practices, nearly twice as many as college football players . </P>

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