www.bbc.co.uk/programmes/b09202lp
I heard PM in radio 4 discussing this research, it seems to hugely benefit girls in terms of their views on their own achievements and the achievements of women in general.
Will listen with interest.
What surprised me (as we have had this language banned in my place of work, with children) is that the teacher, pre experiment, called girls sweetie and petal, and boys buddy etc.