The Layout of the Gap Stores

Most of the Gap stores all have the same look and layout; guys on the right side and girls on the left. Have you ever noticed that is always the same for the majority of stores? Structure was the only store I can remember that had guys on the left. I wonder who decided on this socially acceptable mean. I know it's comfortable and natural for me as a guy to always go to the right when I walk into a store so I guess it's natural for a girl to go to the left when they walk into a store. My real question is if it is politically correct to have ladies on the left?