This study examined knowledge of AIDS transmission, attitudes toward interacting with people who have AIDS, and concerns about being personally affected by AIDS in childhood and adolescence. Subjects were 188 children and adolescents ranging from 6 to 18 years old. An open-ended interview covering a wide range of AIDS-related topics was conducted with each child. Participants then completed a structured interview on the same topics, measuring their knowledge of AIDS transmission and attitudes related to AIDS. Cluster analysis indicated that first and second grade children entertained a wide range of hypotheses about the causes of AIDS but also believed that widely-publicized AIDS risk factors and saliva exchange were the most probable causes. With age, children learned more about risky behaviors and weeded out bad ideas until they approximated the accepted scientific theory. Increased knowledge of AIDS causality caused greater willingness to interact with infected individuals and decreased anxiety about being infected. Cluster analysis suggested that distinguishable subgroups of children exist at each age level, each with a qualitatively different theory of HIV transmission. The data suggests that knowing a child's theoretical perspective on AIDS causality allows for better prediction of receptivity to interacting with people who have AIDS. (Contains 28 references.) (MM)