Experts have provided suggestions on when and how to toilet train children.
"Toilet training is felt to be a natural process that occurs with development, yet very little scientific information is available for physicians who care for children," wrote Dr. Darcie Kiddoo, Divisions of Pediatric Surgery and Urology, University of Alberta, Edmonton, Alberta.
"In reality, toilet training is a complex process that can be affected by anatomic, physiologic and behavioural conditions," he wrote.
Methods have varied over the last century from passive and unstructured to punishment-oriented and regimented.
The current child-centred approach has resulted in children being toilet trained at an older age than previously.
Other approaches include assisted toilet training in babies, operant conditioning with rewards for dryness and punishment for accidents, and a four-step method involving increased fluid intake, scheduled toileting, positive reinforcement and overcorrection of accidents.
Toilet training should be started when both the child and parents are ready.
Both the American Academy of Pediatrics and the Canadian Paediatric Society recommend starting when a child is 18 months old and shows interest in the process.
There is some evidence that indicates more negative outcomes in children who started toilet training late (after age 2 or 3 in various studies.)
Negative outcomes associated with toilet training include refusal to void stool, hiding while defecating, leakage and daytime wetting or urinary tract infections.
The study appeared in Canadian Medical Association Journal.