exposure to media leads to teen sex: you'd think people would eventually learn how not to be idiots about stuff like this, but they never do. ok then: the (supposed) fact that teenagers who watch more people have sex on television have more sex themselves could mean a few things. it could mean that tv causes sex. it could mean that kids who are especially horny tend to watch television with sexual content; that seems intuitive, and is compatible with, for example, the idea that they have less sex than they would if they watched less sex on television, which is also a plausible notion. or it could be that the two phenomena are caused by an entirely other set of variables; for example, that children who watch a lot of television and have a lot of sex have less supervision or perhaps religious or moral training than other children, in which case of course there need be no causal relation between the tv and the sex.