Thumb sucking and nail-biting early in life may reduce allergies later in life. Linus’ thumb-sucking habit just might reduce his risk of common allergies. An article in Pediatrics found that kids who had their fingers in their mouths at ages 5, 7, 9, and 11 years old were less likely to have a reaction to a skin prick test for allergies later in life (ages 13 and 32 years) [1]. Study participants were pricked with common allergens including: house dust mites, grass, cat, dog, horse, wool, and several fungi at ages 13 and 32.