It is a developmental phase that parents can't control. I was a Barbie playing tomboy who loved playing army with all of the boys in the neighborhood in the 50's and 60's. I had an independent streak, too. I don't have daughters, but I think I might have tended to trying to steer a daughter away from girly-girl things when I was younger. However, I found out that you just can't control this stuff. I forbade toy guns, etc. and one kid is a Marine. I guess I never should have allowed those little green plastic soldiers he used to play with for hours, while the other one was reading or doing science experiments!