Your doctor, up until a year old checks your babies legs by moving them up and down and apart. I had never really questioned why this was done but now I know! If caught early - before 6 months - there is a great chance it can be corrected by a Pavlik Harness. If that doesn’t work then their hips are placed in the correct position and the baby is put in a hard fiberglass body cast. If it is gone untreated it could lead to painful hip arthritis later in life and /or a limp in your child’s walk.