The first thing you need to do is find someone who understands statistics well enough to tell you whether the results are truly statistically different, when factoring in such things as sample error, etc.
If in fact the results show a statistically valid difference, then my speculation would be that a second level sociological difference or differences, such as parents in affluent families encouraging female leadership which would include sports participation, is/are the cause(s).
Also, I must say that I am surprised these posts have not raised the ire of the board police, who have always shooed these discussions to the public/private board. I'm not against it, I'm just surprised.