Thumb-sucking and nail-biting might prevent allergies

If you’re a parent, you might want to think twice about shooing a thumb from your child’s mouth. Researchers in New Zealand have found that children who suck their thumbs or bite their nails are less likely to develop allergies later in their lives.

The research comes from a long-term project known as the Dunedin Multidisciplinary Health and Development Study, which has followed more than 1,000 children from Dunedin, New Zealand, since birth. The study is now in its fifth decade.