Thumb-sucking for kids - Thumb-sucking is normal in babies and young children. A natural sucking instinct leads some babies to suck their thumbs during their first few months of life, or even before birth. Babies may also suck on their fingers, hands, or items such as pacifiers. Thumb-sucking in children younger than 4 is usually not a problem. Children who suck their thumbs frequently or with great intensity after the age of 4 or 5 or those who continue to suck their thumbs after age 5 are at risk for dental or speech problems. In rare cases, thumb-sucking after age 5 is in response to an emotional problem or other disorder, such as anxiety. A child with this type of problem needs to be evaluated by a doctor. Most other children stop sucking their thumbs after simple treatment measures are introduced.