The groups referred to are Scouts groups i.e. all Scouts groups since 2007 must be co-educational.
This from an article published a year ago...
Guiding UK's Liz Burnley... tells me the Guides have remained single-sex because it enables girls to mature better. They regularly conduct "Girls Shout Out!" surveys to ask girls for their views. But the overwhelming response is: boys can be loud and aggressive, and won't listen to girls. "They have repeatedly told us they want a girls-only space, to really be themselves."
"The single-sex policy remains a good one, I think," says Diana, a magazine journalist, now 40. "Allowing tweenies and teens one arena where there are free from the pressure to look good and impress boys has to be a positive thing. When kids are under so much pressure to achieve academically and have such a huge and prescriptive curriculum, I think the most important thing the movement can offer girls today is somewhere to have that rare commodity: uncomplicated fun in a safe environment."
http://www.independen...e-better-1942867.html