The medical fact is that the ability to control bladder and bowel functions is individual to each child. Some two-year-olds are fully using the toilet, and some are not. The average age of readiness varies among all children, and even differs between girls and boys. The physical maturity and readiness skills needed for successful toilet learning appear at the same time in girls and boys, typically between the ages of 18 and 30 months. The average age for girls to complete training is 29 months, and 36 months for boys, but these are just averages. The time is right when a child naturally begins displaying signs of toilet readiness, and their family is physically, emotionally, and environmentally ready for the learning to begin.