Fact: One of the men's greatest weakness are their eyes. Their eyes wander everywhere especially when they see something 'interesting' about the opposite sex, women ( Well, the most interesting part is women like to be praised and boys like to see their beauty. So it all makes sense that there is a connection between men's and women's weakness :D)
According to The Telegraph, there are several factors:
Boys don't fit with the curriculum because they are very active and louder at school age. Public school curriculum may not be teaching ‘to the boys’ and that teaching styles are more suitable for girls. (they have to sit around and listen to the teacher)
Boys are more exposed to video games
At school age, average boys are already developmentally two years behind girls in reading and writing. Yet they are expected to learn the same things in the same way at the same pace.