New parents who clean their homes very often to protect their babies from bacteria and other organisms might want to cut back their efforts. A new study suggests that high levels of contact with cleaning products are linked to an increased risk of the childhood breathing condition known as asthma. Researchers asked a group of parents how often they used 26 common household cleaners during their babies’ first three to four months of life. By age three, the children who had come in contact with cleaning products the most were more likely to be diagnosed with asthma. The researchers said that children who had a lot of contact with cleaners were 37 percent more likely to have asthma than children with the least contact.