Although there is no consistent evidence linking different parenting patterns to the onset of delinquency at various ages, there is a great deal of evidence that childrearing styles are among the best predictors of all juvenile delinquency. Harsh or erratic parental discipline; cruel, passive, or neglectful parental behavior; poor child supervision; and parental conflict, measured at age 8, predicted official and self-reported delinquency. Research indicates that parent training can decrease child problem behavior, with the years between a child's birth and age 10 being the most useful for parent training. The same results, however, have not been shown between parent training and reduced delinquency. There is no well-designed experiment with adequate numbers of children and an adequate followup period that has investigated whether parent training decreases delinquency. The promise of parent training justifies its expanded use, with the juvenile court playing an important role, but significant expansion should be preceded by well-designed, experimental research that determines the effectiveness of various training methods. 39 references.