Scientists hope the new information can be used towards prevention.
Boys may be more likely than girls to have childhood asthma. But they are also more likely to grow out of it during adolescence. Harvard researchers looked at over 1,000 children over nine years. They gave the children drugs to test their airways and found that as boys got older it took more of the drug to induce asthma-like symptoms. Girls only showed little improvement. By age 18, the boys improved 13 percent more than the girls.