This single-site, within-subject, experimental study is designed to test the hypothesis children who live in a household in which one or both of their parent smoke will exhibit a higher cough threshold and will prefer more intense sweet tastes than children who live in a household where neither parent smokes. Subjects will include at least 50 racially and ethnically diverse, healthy children aged 10 to 17 years (a critical time for experimenting with tobacco) and a parent. The sample will comprise two groups: Non-Environmental Tobacco Smoke (ETS) Exposed (neither the child nor parents has ever smoked or been exposed to environmental tobacco smoke (ETS) in the home), and ETS-Exposed (the parent has smoked at least 3 cigarettes per day for at least five years in the home, with the child living in the home continuously). Cough sensitivity will be measured using a standard single-inhalation challenge, a test of the minimum concentration of capsaicin (the spicy chemical in hot peppers) needed to elicit cough. Sweet taste preferences will be measured using a forced-choice paired comparison method of liquids which differ in sucrose content. Measures of breath carbon monoxide will validate the smoking status of parents and their adolescent children. The key comparison will be between Non-ETS Exposed and ETS-Exposed children, with the difference between smoking and non-smoking parents as a positive control. Because smoking and non-smoking families may differ in ways besides tobacco exposure, the investigators will obtain health histories (with a focus on respiratory illness), smoking histories, measures of body weight, diet, and responses to personality tests (including susceptibility to addiction). The investigators will also obtain genomic DNA from saliva samples. Genes for chemosensory receptors that are part of the cough reflex pathway and genotype may account for aspects of cough sensitivity.