Thumb Suckers Boost Controversial, Unproven Theory

A new study on the possible health benefits of thumb sucking bolsters the decades-old, controversial "hygiene hypothesis," which claims that exposure to some bacteria early in life could improve health down the road. The latest results come from the Dunedin Multidisciplinary Study, which has followed more than 1,000 people in New Zealand over four decades. Researchers from the University of Otago used the data to see if thumb-sucking and nail biting, both common childhood behaviors, were