Adolescents are influenced by a variety of social factors and institutions. Prior research confirms what many of us know instinctively: that parents can be one of the strongest influences in adolescents' lives. For example, higher levels of parental involvement in their adolescents' lives are linked with lower levels of delinquency, violent behavior, high-school dropout, and drug abuse, as well as with higher levels of educational attainment. In this "Research Brief," we look specifically at whether parental involvement in adolescence reduces the chances of teens being sexually active at a young age. Compelling reasons exist for exploring this topic. Early adolescent sexual experience is linked with a variety of risky outcomes, including acquiring a sexually transmitted infection (STI) and having an unintended pregnancy. Because of the significant role that parents can potentially play in influencing their teens to delay having sex--thus reducing the risk of negative reproductive health outcomes--it is important to understand whether and how multiple dimensions of parental involvement are associated with the timing of teens' first sexual experience. To further this understanding, Child Trends analyzed data from the National Longitudinal Survey of Youth--1997 cohort to explore how parenting practices that occur before adolescents become sexually experienced are associated with the probability of sexual experience by age 16. This "Research Brief" reports our key findings. We found that multiple measures of parental involvement and engagement are associated with delayed sex among teens. These measures include positive parent-adolescent relationship quality, high parental awareness and monitoring, and family dinner routines. Specifically, our analyses showed that adolescent girls who reported higher quality relationships with their mothers and fathers, and adolescent boys who reported that they ate dinner with their families every day were less likely to have sexual intercourse at an early age. The same held true for both adolescent girls and adolescent boys who reported that their parents kept close tabs on whom they were with when not at home. (Contains 8 figures and 2 footnotes.)