I think Anonymous's concern for your future progeny is rooted in homophobia, don't you?  He/She is really saying that if  you let your kid plays with girls and choreograph production numbers that he will turn out gay!

 Which, of course, knowing you, is absolutely fine.

It breaks my heart to see the gender divide happening in my older son's 2nd grade class as well.  He gets along with girls better than boys, mainly because he is a gentle and highly verbal kid.  But now that The Pink has taken hold of the girls, their birthday parties are playdates are gender segregated.