Almost all types of media will expose children to marketing and other forms of persuasive speech which may end up negatively influencing them. While adults are often able to recognize when someone is trying to persuade them to do something that might not be healthy for them to do, children are not.
The most widespread form of persuasive speech is found in the form of advertising. Much content media aimed at children, in particular television programs, magazines and comic books, but also music and software, contains advertisements selling a range of products and services which are specifically designed to inflame children's desires for products they do not need. Also, advertisers frequently will use unrealistic imagery and impossible standards of beauty to sell their products, which can communicate to children that their own bodies are not good enough. Children are not generally able to critically evaluate the claims made by advertisers and avoid claims that are unhealthy for them. For example, children are easily swayed to want to buy sugary breakfast cereals after viewing commercials for those cereals. The rapid fire imagery characteristic of television makes these ads even more vivid and hard to ignore than those appearing in print media.
As children get older, the commercial appeals targeted at them become more sophisticated. There is a constant bombardment of messages telling children that they need to use this newest form of technology to stay updated with friends, to use this newest cosmetic to be attractive, to drink this soda, to eat this junk food, to wear those newest shoes, to subscribe to this online service or that one. It's a constant stream of sophisticated messages featuring glamorous models telling youth that they need these things to be attractive, to be popular, to have fun, and to get ahead. These messages communicate that casual sexuality is fun, exciting, and free of consequences and that only muscular men and thin women with perfect white teeth, bronze tans, clear skin, and styled hair are beautiful. These messages can also include messages about alcohol and drugs (e.g., that alcohol and drugs are glamorous and fun). While it's illegal for alcohol companies to directly advertise to youth, scenes of music and movie stars and video game characters behaving badly and news stories about sports heroes who do the same can send powerful and negative messages to youth. Once again, it is very difficult for youths' brains to think clearly and about what they really need versus what they want, to decide what is healthy for them long-term, and to understand advertisers' money-making motives.