It is said so daughter woman, to the little girl. The slippers are shoes that women wear generally and therefore becomes a metonymy. A credible, but unfortunately most accurate history of origin, is that these sandals are footwear, usually economic, simple and poor quality, for what was used until it broke, something the crowd of field used to occur in the middle of the roads, and then routes were irrigated with flip-flops abandoned on both sides; When an unwanted baby was born it was common to leave it on the banks of the roads so someone pick it, and were almost always girls, why to drink them likened them to the abandoned flip-flops.