Building on previous research implicating the age of onset as a predictor o
f later patterns of delinquent activity, data from subjects participating i
n the Philadelphia Collaborative Perinatal Project (CPP) are combined with
criminal history records from the Philadelphia Police Department to explore
the relationships between gender, early onset, and the seriousness of offe
nding. Findings suggest that an early onset before age fourteen is predicti
ve of serious offending by age eighteen, with the earliest onset ages relat
ing to the most severe delinquency patterns. This relationship holds in the
full sample after controls for relevant variables: however after controlli
ng for variables considered in the full sample model, the early onset - ser
iousness of offending relationship holds for males, but vanishes for female
s. The theoretical and policy implications of these findings and potential
directions for future research are discussed. (C) 2001 Elsevier Science Ltd
. All rights reserved.