Schools are very sensitive to the rapid social, economic, and demographic changes that the United States is presently undergoing. They are at a disadvantage compared to most other social institutions because, in serving a younger population, they have less lead time to prepare for changes in the complexion of society. Young people in today's world face a barrage of challenges and stresses that may prevent them from attaining their full academic potential. A large number of children arrive at school mentally or emotionally unprepared to learn what is being taught. Some have been abused or neglected, others lack English proficiency, and still others come from families that have no home or are forced to live in unsafe neighborhoods. Pregnant teens, teen parents, and youth with drug or alcohol problems are at high risk of school failure or dropping out. These factors are presented in their own sections: social and economic context, racial/ethnic diversity, linguistic diversity, changing family patterns, poverty, homelessness, teen pregnancy, availability of drugs and alcohol, violence and school safety, factors that inhibit risky student behavior, and demographic planning. (RT)