Of all the media, television ranks as the most significant. By the time teenagers reach 70 years of age, they will have spent 7 years of their lives watching television. Teenagers spend more time in front of the television than in formal classroom instruction. Because teenagers spend only 10 to 15 percent as much time watching movies as they do television, movies represent a less significant medium. Next to television, radio probably ranks second in importance to teenagers who average 3.7 hours on weekdays and 6.4 hours on weekends listening to the radio. Print media advertisements are guilty of many of the same shortcomings as television programming. Cigarettes are deceptively advertised, and sex is used without regard to the product advertised but simply to gain the attention of readers or listeners. Many studies have attested to television's ability to transmit information and shape attitudes. Adolescent attitudes are malleable, and television can give teenagers their first real glimpse of the adult world long before they can learn about it firsthand. Children model their behavior after adults; if children see an adult rewarded for a certain behavior, they are more likely to imitate that behavior. Several studies have consistently linked television violence and aggressive behavior in children and adolescence. The media, especially television, may also contribute to adolescent suicide. Television has become the leading sex educator in the United States; only 10 to 30 percent of school systems offer comprehensive sex education, and only a small number of parents discuss sex in detail with their children. The link between viewing sex on television and teenage pregnancy, however, is not definitive. Graphic lyrics of rock-and-roll and music videos have a further effect on teenage attitudes and behavior. Countering the negative influences of media messages must involve parents, primary care physicians, schools, the television industry, the Federal Government, and society as a whole. 154 references, 12 tables, and 6 figures