The prediction resulted from the documented negative association between maternal age and aggressive, overactive, and oppositional behavior of the child and the positive association between this externalizing behavior in childhood and the probability of later juvenile delinquency. The data came from the statistics on index crimes reported by Bureau of Justice Statistics during 1987-97 and from data on maternal ages during 1970-80 as reported by the National Center for Health Statistics. Results revealed a close resemblance between these time series. The analysis concluded that it was not possible to assert causality from two different time series, but the existence of such a relationship was plausible. Possible hypotheses regarding causality were that older mothers had a different style of raising children than did younger mothers and that younger mothers exposed their fetuses to relatively greater amounts of maternally produced masculine hormone testosterone. Figure, footnotes, and 12 references (Author abstract modified)