Young people, 8 to 21, are a major U.S. consumer group across virtually all industries. They have great purchasing power, to the tune of $139 billion annually, and the influence they exert on their families’ purchase decisions is enormous.

Advertising and media images that encourage girls to focus on looks and sexuality are harmful to their emotional and physical health, a new report by the American Psychological Association says.

MTV prospered for decades because it looked like what a network might look like if a 16- year-old were doing the programming.