Throughout the world pregnancy and childbearing are occurring at younger ages than in the past, resulting in adverse health, demographic and social consequences. Postponing first births until age 20 or later would significantly reduce maternal and infant mortality and morbidity, slow population growth, and contribute to improvements in the quality of life for people everywhere. This conclusion is based on an examination of the problems associated with adolescent sexuality and fertility. This report provides background to these problems, analyzes current trends, and specifically discusses the medical risks of early pregnancy, demographic and social consequences of early childbearing, delivery of family planning services, contraception and abortion for adolescents, and sex education. The report concludes with a comprehensive bibliography. (Author/SJL)