Children's ear infections can be quickly cured, but there may be lasting effects. In a study of more than 7,500 kids ages 2 to 11, University of Illinois at Chicago scientists found that children who suffered three or more ear infections in their lifetime were twice as likely as children with no ear problems to have asthma. It's not clear what the two diseases have in common, but one possibility is that the bacteria that cause ear infections may play a role in the development of asthma. It could also be that the antibiotics used to clear up ear infections somehow increase a child's asthma risk. The study showed that children's ear-infection rates go up as their parents' education level increases, possibly because those kids tend to spend more time in day care.