A long-held theory that antibiotic use in the first year of a childs life can cause asthma may have been disproved. A study published in The Lancet today explains that although children who use antibiotics are indeed at increased risk for asthma, the antibiotics themselves might not be at fault. Rather, the reason for the connection might have to do with the presence of genetic variants on a specific region of chromosome 17. As The New York Times then explained, the researchers thought that the antibiotics might be killing bacteria that contributes to the development of a healthy immune system, in addition to those that are harmful. But the study published today clarifies the link by suggesting that impaired antiviral immunity and genetic variants on a region of chromosome 17 might be the source of both the asthma and early antibiotic use.