I'm worried that my son may be endangering his friendship with your daughter. He's told us that there is a secret club of girls who say "too-too" or the like when he and his buddy are together. This secret club is run by your daughter. How many members? "All of them." He got really annoyed when I asked how many girls actually say "tutu." "ALL OF THEM!" he yelled.
I suspect that on one or two days your daughter and maybe a few other girls might have said "Two two" as a celebration of my son and his pal.
But now I think, my son and his pal really love this idea of a girl conspiracy. They're at the right age to begin making girls the enemy. My son has begun planning a birthday party to which no girls would be invited -- well, except his best friend Julia. The entire agenda for the party would be to discuss countermeasures against the tutu club.
I am NOT asking you to talk to your daughter or change her behavior. I am just hoping that we parents can undermine the splitting into rival genders a bit.