As with normal reflexes, most school-age children have tongue thrust if looked for. For example, according to recent literature, as many as 67–95 percent of children 5–8 years old exhibit tongue thrust, which may professionally be represented as associated with or contributing to an orthodontic or speech problem - depending on the clinical bias of proposal. Up to the age of four, as with the complex conversion of all simpler reflex events, there is a possibility that any observed child will normally outgrow tongue thrust as they transition to a fuller dentofacial development. However, if a tongue thrust pattern is retained beyond infancy, it can be seen through a lens of abnormality, and this vulnerable to clinical bias and attempts to clinically interact.