Teachers tend to grade those of the same gender more leniently. Boys appear to be aware of this fact [View all]

Abstract: Our results show systematic gender interaction effects: male students invest less with female teachers than with male teachers while female students invest more with male teachers than with female teachers. Interestingly, female students’ perceptions are not in line with actual discrimination: Teachers tend to give better grades to students of their own gender. Results do not suggest that ethnicity and socioeconomic status play a role.

Full paper: http://www.insead.edu/facultyresearch/research/doc.cfm?did=48404

Basically boys are aware that female teachers will judge them more harshly and are more willing to give up without trying.
With male teachers they (accurately) do not perceive a bias against them.

Whereas girls interestingly enough expect preferential treatment from male teachers (inaccurate) and are unaware (apparently) of the preferential treatment they actually get from female teachers.

As far as I am aware there is no national movement to correct the gender gap wherein boys perform poorly compared to girls nor is there any effort towards achieving demographic parity among our teaching staff.

Being denied equal access to education: check your privilege.