In the early seventies there was a major research on the effect of single sex education and the school I attended (all girls) was one of those included in the study. Its findings were that girls performed better on average in a single sex environment whilst boys generally performed better in a mixed class!! Sometimes it just isn't possible to have the perfect solution. On the whole I am against any division by sex or race but isn't this just an extension of special needs provision?
Amongst adolescent boys being academic is not always seen as 'cool' so maybe the real task should be to change these perceptions and actually help these youngsters to see that education has a value and not just as a way of getting a job because they will soon turn round and tell you that this is not the case! Moving away from a national curriculum so that teachers can use their professional judgement to adapt learning to students interests and needs whoever they are might be a good start. Most schooling (as opposed to education) these days is about jumping through the right hoops and improving schools position on the league tables which ultimately affects their funding.