I teach in a mixed rural school and when I first joined the staff the school had a boys football team where they competed with other local schools. Due to declining number of boys in the school, the team then became a mixed football team. Initially the boys, particularly the older classes did not welcome the girls as it was perceived girls were not good at soccer and should have their own team. However, some of the girls are fantastic and could easily beat any of the boys!
Once the team was formed, the boys changed their attitude towards playing and now are much more inclusive. I think the concept of all girls/ all boys teams are very old fashioned and biased and do not foster inclusivity. I think sport stars such as Katie Taylor are doing fantastic work to break down barriers and mis conceived notions that girls are not as competitive or talented as boys at sport.