I can't say any more as I don't want to lose my anonymity, but I have written a lot about the benefits of single sex education for boys.
Some articles on the subject (culled from lefty Observer and the Torygraph, so it's not party political!)
www.guardian.co.uk/education/2008/apr/27/schools.uk
www.telegraph.co.uk/education/main.jhtml?xml=/education/2003/04/01/tencoed30.xml
The Independent:
"Some schools believe that their experiments in teaching single sex have improved boys' performance
For example, the Pingle School, a comprehensive in Swadlincote, Derbyshire, first introduced single sex teaching two years ago because of concerns about a class of 12-year-olds who were behaving badly. The year group was segregated for 70 per cent of their lessons. After a term, 85% of boys and 82% of girls said they preferred being taught this way. Behaviour improved 'phenomenally' according to Mike Mayers, the headteacher, and 45% of the year group are now expected to achieve five grade A to Cs at GCSE, compared to a forecast of only 29% when the monitoring started. With monitoring by Loughborough University, the school now segregates all its 11 - to 14-year-olds for 80% of lessons and GCSE students are taught in single-sex classes for English, maths and science."
Whatever the reason, it seems to work!