This guide discusses the importance of parent influence in preventing teen pregnancy, offering insights from research regarding: closeness between parents and their children; parent-child communication; parental attitudes and values about abstinence and/or the dangers of unprotected sex; parents' reluctance to discuss the issue; parental supervision of teens' behavior; parent and peer influence; family structure and where the family lives; other risky behavior; parents' lack of awareness of their children's sexual behavior; dating dangers; a national consensus on preventing early sexual activity and parenthood; and limits on what public schools can do. Overall, parents who clearly communicate their values and expectations to their children, express their concern and love for them early and often, and exercise supervision raise children who are more likely to avoid a host of risky behaviors than parents who do not. The paper presents facts that teens want adults to know (e.g., telling them not to have sex is not enough, paying attention to them before they get into trouble is important, and adolescents care about what parents have to say, even if they do not always act like it). Tips for parents include be clear about one's sexual attitudes and values, be a parent with opinions, and discourage early, frequent, and steady dating. (SM)