I slightly disagree with the above comment of how Girls schools boost girls' skills and confidence levels, and do support the article in how well a mixed school can positively affect the students.
As a mere spectator of social dynamics, anyone may observe the necessity of students' exposures to differences whether in gender or abilities at school. This is the core foundation beneath which lies the silent teaching of morale, respect, self image and confidence, and above all proper understanding of the opposite gender. As well, egoistic feelings develop and create a positive sense of academic competition or even sports achievement, which in turn pushes all other class members higher up the grid. These very feelings arise when opposite genders manifest those instinctive needs, but of course in a controlled manner through which society and parents play a key role in also developing.
Thus, to say a boys only or girls only school is of great advantage, is to neglect the various aspects of a healthy uunderstanding and proper means of raising awareness and developing character.