The first cases of AIDS in children were reported in 1982 and involved a transfusion recipient and four infants born to women at increased risk for AIDS. Infants may acquire their infection perinatally or possibly postnatally through infected breast milk. Parenterally acquired infection, through transfusion of blood or blood products, occurs in infants, children, and adolescents. Adolescents are also at risk for infection through sexual transmission and through shared needles among intravenous drug users. By January 1987, 1.4 percent of the AIDS cases were in children less than 13 years old, and 0.4 percent were in adolescents 13 to 19 years old. Additionally, 4.4 percent of the total AIDS cases were reported in 20 to 24 year olds, which most likely reflects infection which occurred during adolescence. In children less than 13 years old, infection occurred primarily through perinatal transmission from mothers who were intravenous drug users or sexual partners of intravenous drug users. Adolescent cases of AIDS have followed adult patterns of transmission with most cases resulting from sexual transmission. As the prevalence of infection with the human immunodeficiency virus increases, increases in drug-use-associated transmission in women followed by perinatal transmission to infants and sexual transmission in adolescents seems likely to occur. To prevent further spread, health agencies must develop and target extensive AIDS prevention campaigns at adolescents, young adults, and sexually active women. 5 tables. 61 references. (Author abstract)