CHICAGO, Illinois (Reuters) -- Teenagers who watch a lot of television with sexual content are twice as likely to engage in intercourse than those who watch few such programs, according to a study published Tuesday.The alternative, of course, is that teenagers who opt (and who have families that allow them to opt) into watching television with a lot of sexual content are more likely to engage in more teenage sexual behavior.
The study covered 1,792 adolescents aged 12 to 17 who were quizzed on viewing habits and sexual activity and then surveyed again a year later. Both regular and cable television were included.
'This is the strongest evidence yet that the sexual content of television programs encourages adolescents to initiate sexual intercourse and other sexual activities,' said Rebecca Collins, a psychologist at the RAND Corp. who headed the study.
'The impact of television viewing is so large that even a moderate shift in the sexual content of adolescent TV watching could have a substantial effect on their sexual behavior,' she added."
Methodological note for the interested: this is a study where the putative causal inference is based on repeated measures of the same individuals, which generally does provide a logically stronger grounds for inference than a study based on a single-point-in-time survey of individuals. However, the study--unless there is an unusual, important wrinkle not included in the media report--actually provides an example of a principal danger of longitudinal data, which is that it is easy to overestimate the extent to which it allows one to make inferences about cause-and-effect. What the longitudinal data really allows you to rule out is the possibility that the correlation is driven by a tendency for teens who have start having sex to then be inspired to increase the amount of sexual content TV they watch, but that's not exactly the worrisome alternative explanation here.