Recent findings in NICHD-supported research illustrate the powerful effects of environmental factors - from television viewing to parental involvement - on children's and adolescents' behaviors and health. Most importantly, however, the findings systematically underscore the critical role that parents can play in making decisions that can preserve and enhance the health and development of their children.

Early television exposure linked to attention problems in children. Researchers have had evidence from cross-sectional studies that television viewing at an early age may be associated with decreased attention span in children. However, they had no data from long-term studies to support this observation until NICHD-funded researchers designed an observational study to test a hypothesis: that television exposure at one and three years of age was associated with attentional problems at age seven. The researchers analyzed data on more than 2,600 children who were part of the National Longitudinal Survey of Youth. Using advanced statistical methods, researchers found that the more television very young children watched, the more likely they were at age seven to have attention problems. The researchers cautioned that since they used a special definition of such problems, their findings did not necessarily indicate that early television viewing is associated with clinically-diagnosed attention-deficit/hyperactivity disorder (ADHD) in the older children. Their findings suggest, however, that parents could reduce the risk of such problems by limiting television viewing of children in the early years, when their brains are still rapidly developing.

Watching television with a high level of sexual content is associated with earlier teen sexual behavior. Researchers found that adolescents who watch television with high levels of sexual content are more likely to initiate sexual intercourse at an early age, compared with peers who view relatively little sexual content.[1] The researchers acknowledge that it's nearly impossible to conclusively prove that the sexual content of television shows influences teen sexual behavior. It's conceivable, they wrote, that teens considering engaging in early sex are simply drawn to TV programming with sexual content. However, the researchers believe this latter possibility is highly unlikely. In the study, which followed almost 1800 adolescents between the ages of 12 and 17, the researchers carefully controlled for factors known to influence early sexual activity, such as academic performance and family structure. In two rounds of interviews, a year apart, researchers found that youth in the 90th percentile of watching "television programs with a high level of sexual content" were twice as likely to initiate intercourse as those in the bottom 10 percent.

Parents can influence adolescents' decisions on whether to start smoking. Researchers have found that direct parental involvement with young adolescents, coupled with perceived parental disapproval of smoking, can influence young people not to start smoking as more and more of their peers do so.[2] These findings are important because rates of smoking initiation among young adolescents remain high, compared with those of adults, and because starting to smoke as an adolescent increases the likelihood that an individual will be dependent on smoking as an adult. Surveys of children at the beginning and end of sixth grade, and at the end of seventh grade, showed that if children thought that their parents generally "kept tabs" on them and would be upset if they knew that their child smoked, they were less likely to smoke, while children who believed their parents to be less involved with them were more likely to smoke.