I have a lot of nephews and nieces and 2d cousins. We all get together over the holidays and its a wild party.
The boys' energy levels vs the girls at the same age is a notch or two higher. Also, boys consistently get timeout and break things where the girls don't - if at all. Its very interesting to observe the differences at all age levels and the changes both sexes go through as they get older. The girls definately have a much higher verbal ability and verbal reasoning.
As for testing, I can see how a test or screening that favors conformity will tend to screen for girls while a test that penalizes independent thought that is acted upon will penalize boys.
