The theory of staring a separate girls' troop is great. The reality is that it won't happen. The troop will become coed. As more and more adults use to a coed Cub Scout program move into the troop, they will see no problem with being a "linked troop," which is national's codeword for coed. They will start promoting the concept, and their numbers grow and/or they get into key positions to implement the change, they will.
The camel's nose is already under the tent flap.