Dear mummies, I understand that there is a chart showing the ergonomic and dangerous ways of baby carriers. For RS, my mother disagree that babies under the age of 4 months should be carried with the M shape. She felt that it would affect her legs development, which may cause her to walk like a duck in future. She is of view that the cradle sling is better for young infants. Any articles to show her that it is dangerous, and that the correct way of wearing a RS will not affect her body structure development? Thanks.