“…This male preponderance, which has remained constant over time 123 , ranges from 1.1:1 to 8.5:1 3,7,9,10,20,21,29,34,36,41,42,[47][48][49]55,57,62,69,71,76,83,88,90,104,108,110,116,117,119,133,134 and has been attributed to greater and more dangerous physical activities among boys 19,[90][91][92]134 . In younger age groups, gender differences are less significant and the etiologies are similar in both sexes.…”