The concept of “adolescence” or “young adulthood” is a relatively recent development. This is particularly true in developing agricultural countries, where the transition from childhood to adulthood is rapid, marked by reproductive maturity and accompanying socioeconomic privileges and responsibilities. An extended period of time spent moving from one life stage to the other is a modern response to expanded education for both men and women, the need for more extensive vocational training, the increasing vocational aspirations of young women, and the recognition that adolescent development deserves investment and special treatment.
The biological events related to sexual maturation are now only part of this life phase. Considerable attention is also being given to psychosocial and behavioral aspects of young adulthood, especially in view of its risk-taking activity and the assumption of unhealthy social habits such as smoking, drug use, and violent behavior. Many of the concerns have intensified in recent decades, because of urbanization, increased exposure to media, and high rates of unemployment, including, in some areas, persistent homelessness and various forms of social upheaval.
Reproductive health is a major concern of the young adult period, in part because earlier sexual maturation and later marriage have increased the period of risk for early or nonmarital pregnancy and exposure to sexually transmitted diseases (STDs), including the likelihood of multiple partners. Changes in familial and societal patterns and values have also resulted in a relaxation of social constraints on nonmarital sexual activity. HIV infection is the most recent, and most serious, addition to the array of STDs common in this age group.