Sexual Abuse: A Journal of Research and Treatment, Vol. 16, No. 4, October 2004 (
Onset, Persistence, and Versatility of Offending
Among Adult Males Convicted of Sexual Offenses
Stephen W. Smallbone
and Richard K. Wortley
Ofﬁcial sexual and nonsexual offense histories and conﬁdential self-report data
on sexual offending were obtained on 207 adult males serving sentences for sexual
offenses against children (98 intrafamilial, 72 extrafamilial, and 37 mixed-type
offenders). The mean self-reported age when offenders ﬁrst had sexual contact
with a child was 32.2 years (median = 31 years; range = 10–63 years). The
mean age at ﬁrst conviction for any offense was 30.5 years (median = 27 years;
range = 12–66 years), and the mean age at ﬁrst conviction for a sexual offense
was 37.3 years (median = 37 years; range = 15–76 years). Sixty-nine percent
(n = 143) of the combined sample had at least one previous conviction, and 80% of
these (n = 114) had ﬁrst been convicted for a nonsexual offense. ANCOVA revealed
a systematic pattern of onset with ﬁrst convictions for any offense preceding ﬁrst
sexual contact with a child. Taken together, results indicate that, in general, adult
child molesters (a) begin sexual offending in their 30s, (b) have already become
involved in nonsexual crime by the time they ﬁrst have sexual contact with a child,
(c) are criminally versatile, and (d) vary considerably in their persistence with
respect to both sexual and nonsexual offending.
KEY WORDS: onset of sexual offending; etiology; expertise.
Criminal-careers research has identiﬁed reliable trends in offending trajec-
tories for delinquency and crime. In broad terms, although delinquency- and
crime-related behaviors can often be traced to oppositional and conduct problems
in early and middle childhood (Mofﬁt, 1993; Tremblay, 2000), both self-reported
and ofﬁcial offending peak in adolescence and early adulthood and decline steadily
School of Criminology and Criminal Justice, Grifﬁth University, Queensland, Australia.
To whom correspondence should be addressed at School of Criminology and Criminal Justice,
Mt Gravatt Campus, Grifﬁth University, Queensland 4111, Australia; e-mail: s.smallbone@grifﬁth.
2004 Plenum Publishing Corporation