I'm the XXY educator, the guy who knows more about XXY and related conditions than even the medical profession's representatives on Dailymotion. <br /><br />You might watch other videos that say Klinefelter's syndrome affects children or that XXY boys are born with Klinefelter's syndrome. You can even find parents of XXY boys saying their children were born with Klinefelter's syndrome, but in reality not all XXY's go on to develop Klinefelter's syndrome, and the syndrome itself when it does develop, doesn't until after the onset of puberty. <br /><br />All that can be said of all XXY's is that they're XXY.