Child Pornography Offenses Are a Valid Diagnostic
Indicator of Pedophilia
Michael C. Seto
Centre for Addiction and Mental Health, Toronto, Ontario,
Canada, and University of Toronto
James M. Cantor
Centre for Addiction and Mental Health, Toronto,
Centre for Addiction and Mental Health, Toronto, Ontario, Canada, and University of Toronto
This study investigated whether being charged with a child pornography offense is a valid diagnostic
indicator of pedophilia, as represented by an index of phallometrically assessed sexual arousal to
children. The sample of 685 male patients was referred between 1995 and 2004 for a sexological
assessment of their sexual interests and behavior. As a group, child pornography offenders showed
greater sexual arousal to children than to adults and differed from groups of sex offenders against
children, sex offenders against adults, and general sexology patients. The results suggest child pornog-
raphy offending is a stronger diagnostic indicator of pedophilia than is sexually offending against child
victims. Theoretical and clinical implications are discussed.
Keywords: pedophilia, child pornography, sexual arousal, phallometry, diagnosis
Justice statistics suggest that the number of child pornography
investigations is increasing (Finkelhor & Ormrod, 2004). Clini-
cians may, therefore, be increasingly asked to assess child pornog-
raphy offenders with regard to decisions about risk, treatment, and
supervision. A particularly germane question in these clinical
assessments is whether the child pornography offender is a pedo-
phile, given the intuitive link between possession of child pornog-
raphy and pedophilia, defined as a persistent sexual interest in
prepubescent children (American Psychiatric Association, 2000).
The present study was conducted to determine whether child
pornography offenses are a valid diagnostic indicator of pedo-
philia. Clinicians currently rely on three potential sources of in-
formation when considering the diagnosis of pedophilia: self-
report, a history of sexual behavior involving children, and
psychophysiological assessment. All of these sources have their
limitations. Self-report regarding an individual’s sexual interests is
the simplest to obtain, but some individuals will deny having
pedophilic interests, given the potential social consequences of
such a disclosure (see Jenkins, 1998). An individual’s history of
sexual offenses, in terms of the number, gender, age, and related-
ness of child victims, is informative (Seto & Lalumie`re, 2001), but
it only approximates the offender’s interests because it is limited to
known victims. The number of documented child victims of sexual
offenses may underestimate the actual number of children with
whom the individual has had sexual involvement, and in some
cases, it is limited to the children who were accessible to the
offender, irrespective of his interests. Psychophysiological assess-
ment methods such as viewing time (e.g., Abel, Huffman, War-
berg, & Holland, 1998; Harris, Rice, Quinsey, & Chaplin, 1996)
and phallometry (Blanchard, Klassen, Dickey, Kuban, & Blak,
2001; Freund & Blanchard, 1989; Freund & Watson, 1991; Seto,
Lalumie`re, & Blanchard, 2000; Seto, Lalumie`re, & Kuban, 1999)
provide an objective method of assessing sexual interests, but they
also can be vulnerable to response suppression.
Thus, identifying new sources of information about pedophilia
would have both clinical and theoretical applications. Child por-
nography offending is a promising candidate indicator, given the
experimentally demonstrated effects of mainstream adult pornog-
raphy exposure on attitudes about women, sexual perceptions, and
aggressive behavior (for a recent review, see Seto, Maric, &
Barbaree, 2001). However, relatively little is known about child
We define child pornography as visual depiction of children with their
genital or anal areas uncovered or of children in sexual situations, consis-
tent with the statutory definitions of Canadian and American legislation
(Sec 163.1 of the Criminal Code of Canada and the American Child
Pornography Prevention Act of 1996). For example, the Canadian Criminal
Code defines child pornography as a visual representation that shows a
“person who is or is depicted as being under the age of eighteen years and
is engaged in or is depicted as engaged in explicit sexual activity” or
displays, “for a sexual purpose, a sexual organ or the anal region of a
person under the age of eighteen years” (Sec 163.1, R.S. 1985, c. C-46).
Michael C. Seto, Centre for Addiction and Mental Health, Toronto,
Ontario, Canada, and Department of Psychiatry and Centre of Criminol-
ogy, University of Toronto, Toronto, Ontario, Canada; James M. Cantor,
Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Ray
Blanchard, Centre for Addiction and Mental Health, Toronto, Ontario,
Canada, and Department of Psychiatry, University of Toronto, Toronto,
We thank Meredith Chivers, Grant Harris, and Martin Lalumie`re for
their helpful comments on an earlier version of this article.
Correspondence concerning this article should be addressed to Michael
C. Seto, Law and Mental Health Program, Centre for Addiction and Mental
Health, 250 College Street, Toronto, Ontario, Canada, M5T 1R8. E-mail:
Journal of Abnormal Psychology Copyright 2006 by the American Psychological Association
2006, Vol. 115, No. 3, 610 – 615 0021-843X/06/$12.00 DOI: 10.1037/0021-843X.115.3.610
pornography offenders (see Jenkins, 2001). Howitt (1995) inter-
viewed 11 adult male pedophiles who reported occasional use of
child pornography. These men said they created their own sexually
arousing materials from images in catalogues, magazines, and
other freely and legally available sources. Quayle and Taylor
(2002) interviewed 13 men convicted of downloading child por-
nography from the Internet. Many of these men acknowledged that
the material they downloaded was sexually arousing to them and
corresponded in content to their sexual fantasies. Galbreath, Ber-
lin, and Sawyer (2002) reported data from 39 individuals who were
assessed at an outpatient clinic because of concerns about their use
of the Internet for sexual purposes. All had used sexually explicit
Web sites, and the majority (64%) had participated in sexually
explicit chat rooms. Fifty-five percent of the outpatients had down-
loaded child pornography, and 34% had attempted to meet a minor
for sex. Seto and Eke (2005) followed a sample of men charged
with child pornography offenses and found that those who also had
a history of other criminal involvement were more likely to reoff-
end during the follow-up period (average 2.5 years) than were
those with only child pornography offenses in their history. Not
surprisingly, those with a prior history of sexual offenses involving
contact with a victim were the most likely to sexually reoffend.
The present study was conducted to determine whether being
charged with a child pornography offense is a valid indicator of
pedophilia. We predicted that men charged with a child pornog-
raphy offense (child pornography offenders) would show greater
sexual arousal to children during phallometric testing than would
men with no history to suggest pedophilia (i.e., men who had
committed sexual offenses against victims aged 17 or older only;
offenders against adults) and men who had been referred for
sexological evaluations because of concerns about their sexual
interests or behaviors (e.g., compulsive use of prostitutes or com-
mercially available pornography; general sexology patients). In
contrast, we expected child pornography offenders to be similar in
their patterns of sexual arousal to men who had committed sexual
offenses against child victims aged 14 or younger (offenders
We obtained data for 685 patients assessed at the Kurt Freund Labora-
tory of the Centre for Addiction and Mental Health (Toronto, Ontario,
Canada). This laboratory provides comprehensive evaluations to males
referred as a result of illegal or clinically significant sexual behaviors. The
primary source of referrals to this facility was parole and probation officers
(36%), followed by lawyers (24%), self-referral through a physician (21%),
and correctional institutions (18%).
The initial sample consisted of 887 men; 202 did not produce a valid
result on the phallometric test used in this study (e.g., refused to participate
in the assessment, equipment malfunction, lack of any response to any
sexual category) and were dropped from the analysis. Sex offenders with
victims who were 15 or 16 years old were not included in the initial search
of the database. The study sample of 685 men had mean and median ages
of 36.8 years (SD ⫽ 12.0) and 36.0 years, respectively. The median
educational level was high school graduation; a third had not graduated
high school, and a third had completed some college or university schooling.
The patients were predominantly of European descent, with 79.1% describing
themselves as White, 6.1% as Black, 4.7% as Indian or Pakistani, 2.2% as
Southeast Asian, 1.5% as Aboriginal Canadian, 1.3% as Filipino or Pacific
Islander, and 5.1% as “other,” which included mixed ancestry.
Of the 685 patients in the study sample, 100 had charges for child
pornography offenses (child pornography offenders); of these men, 57 had
no known sexual offenses against children, whereas 43 had sexual offenses
against one or more children. Another 178 men had no history of charges
for child pornography but did have a history of one or more sexual offenses
against victims who were aged 14 or younger (offenders against children),
216 men had no history of charges for child pornography or sexual offenses
against child victims but did have a history of sexual offenses against
victims who were aged 17 or older (offenders against adults), and 191 men
had no history of charges for child pornography or sexual offenses (general
The standard evaluation at the laboratory consists of a phallometric
assessment of the patient’s sexual interests, a semistructured clinical in-
terview, and a review of mental health and legal documents supplied by the
referral source. The evaluation also includes a brief neuropsychological
battery that is unrelated to the present investigation (see Cantor et al.,
2004). On completion of his evaluation, each patient was invited to permit
his clinical data to be used for research purposes.
Sexual offense history. File information was reviewed to identify pa-
tients who had been charged for child pornography offenses. In addition,
phallometric laboratory staff used a standardized form to record each
patient’s history of sexual offenses against child or adult victims. The
sexual offense information came primarily from collateral documents such
as reports from the police, probation, or parole officers. Some patients
admitted having additional victims who were not recorded in their files and
for whom they had not been charged; these additional victims were added
to the victims known through file information.
Phallometric testing. Clinicians and researchers use phallometry to
quantify the sexual interests of sexual offenders against children (e.g.,
Howes, 1995). A meta-analytic review of 61 sex offender follow-up studies
found that phallometrically assessed sexual arousal to children was the
strongest predictor of subsequent sexual offenses among all the variables
that were examined (Hanson & Bussie`re, 1998).
The specific protocol in use at the Kurt Freund Laboratory over the
course of the present investigation reliably distinguishes pedophilic from
teleiophilic men (i.e., men who prefer sexually mature persons). Blanchard
et al. (2001) have described the phallometric testing procedure and data
preparation in detail. Briefly, a computer records penile blood volume
while the patient observes a standardized set of stimuli that depict persons
of potential sexual interest. Changes in penile blood volume (i.e., his
degree of penile erection) indicate his relative sexual interest in each
The stimuli used in the phallometric test were slides accompanied by
audiotaped narratives presented through headphones. There were seven
categories of slides, six of which depicted nude models representing the
following combinations of sex and age: female adults, female pubescent
children, female prepubescent children, male prepubescent children, male
pubescent children, or male adults. The seventh stimulus category was
neutral slides depicting landscapes. Each slide was accompanied by a
narrative describing sexual interactions with the depicted person, except for
the neutral slides, which were accompanied by a narrative describing
solitary, nonsexual activities.
The data reduction process yields seven phallometric test scores, one for
each of the seven stimulus categories. These phallometric test scores are
ipsatively standardized; that is, each patient’s phallometric test scores are
transformed to have a mean value of zero and a standard deviation of one,
consistent with the recommendation of Harris, Rice, Quinsey, Chaplin, and
Earls (1992) regarding the optimal treatment of phallometric data. Phallo-
metric test scores greater than zero indicate that the participant responded
to the category above his own average response, and scores below zero
indicate the participant responded to the category less than his own average
CHILD PORNOGRAPHY AND PEDOPHILIA
response. Finally, a pedophilic index was calculated for each patient: The
pedophilic index was the difference between his greatest response to any of
the four child categories and his greatest response to either of the two adult
We first assigned participants to nine groups on the basis of their
sexual offense histories. There were 57 child pornography offend-
ers without a history of sexual offenses against children; 43 child
pornography offenders with a history of sexual offenses against
one or more victims aged 14 or younger; 131, 36, and 11 offenders
against children with one, two, or three or more victims aged 14 or
younger, respectively; 101, 35, and 80 offenders against adults
with one, two, or three or more victims aged 17 or older, respec-
tively; and 191 general sexology patients. The last comparison
group was included because we have found in previous research
that, as a group, general sexology patients show a teleiophilic
sexual preference for adult women (Blanchard et al., 2001; Seto et
There was a difference between groups in their referral source:
The majority of child pornography offenders without a history of
sexual offenses against children were referred by their lawyers
(70%), whereas the majority of child pornography offenders with
a history of sexual offenses against children were referred by
probation or parole officers or correctional institutions (82%). In
comparison, a slight majority of offenders with child or adult
victims were referred by probation or parole officers (52%), and a
majority of general sexology patients were self-referred (67%).
The proportions of men in each of the nine study groups—two
groups of child pornography offenders, three groups of offenders
against children, three groups of offenders against adults, and one
group of general sexology patients—who met a diagnostic crite-
rion for pedophilia used at the Kurt Freund Laboratory (pedophilic
index greater than .25; Blanchard et al., 2001) are shown in Figure
1. There was a significant difference between groups in the pro-
portions who met this diagnostic criterion: 61% of child pornog-
raphy offenders, 35% of offenders with child victims, 13% of
offenders with adult victims, and 22% of general sexology pa-
(3, N ⫽ 685) ⫽ 86.77, p ⬍ .001. In other words, child
pornography offenders had almost three times the odds (odds
ratio ⫽ 2.8) of being identified as a pedophile phallometrically
than did offenders against children. The corresponding odds ratios
were 10.5 when comparing child pornography offenders with
offenders against adults and 5.7 when comparing child pornogra-
phy offenders with general sexology patients.
We also compared the same nine groups in their absolute
phallometric responses (penile volume change; in cc) to any
stimuli depicting children and to any stimuli depicting adults
(see Figure 2). Consistent with the results from the analysis of
pedophilic indices, child pornography offenders responded sub-
stantially more to stimuli from categories depicting children
than to stimuli from categories depicting adults. In contrast,
Figure 1. Proportion of child pornography offenders, offenders against children, offenders against adults, and
general sexology patients identified as pedophilic according to the phallometric test.
SETO, CANTOR, AND BLANCHARD
offenders against adults and general sexology patients re-
sponded more to stimuli depicting adults than to stimuli depict-
ing children. Offenders against children with three or more
victims also showed a greater absolute phallometric response to
children than to adults.
We then combined the three groups of offenders against chil-
dren and the three groups of offenders against adults and compared
the resulting five groups—two groups of child pornography of-
fenders, a combined group of offenders against children, a com-
bined group of offenders against adults, and one group of general
sexology patients— on their average pedophilic indices. Consistent
with the results depicted in Figure 1, there was a significant
difference between groups in their average pedophilic index, F(4,
680) ⫽ 24.21, p ⬍ .001 (see Figure 3). Examining the 95%
confidence intervals, both child pornography offender groups had
average pedophilic indices indicating significantly greater sexual
arousal to a category depicting children than to a category depict-
ing adults (i.e., the two child pornography offender group means
did not overlap with zero). The two child pornography offender
groups did not significantly differ from each other, but they had
significantly higher average pedophilic indices than did the other
three groups. As found in many previous studies, offenders against
children had significantly higher average pedophilic indices than
did offenders against adults or general sexology patients.
Our results indicate that child pornography offending is a valid
diagnostic indicator of pedophilia. Child pornography offenders
were significantly more likely to show a pedophilic pattern of
sexual arousal during phallometric testing than were comparison
groups of offenders against adults or general sexology patients. In
fact, child pornography offenders, regardless of whether they had
a history of sexual offenses against child victims, were more likely
to show a pedophilic pattern of sexual arousal than were a com-
bined group of offenders against children.
Our results suggest that child pornography offending might be a
stronger indicator of pedophilia than is sexually offending against
a child. A possible explanation for this finding is that some
nonpedophilic men victimize children sexually, such as antisocial
men who are willing to pursue sexual gratification with girls who
show some signs of sexual development but are below the legal
age of consent. In contrast, people are likely to choose the kind of
pornography that corresponds to their sexual interests, so relatively
few nonpedophilic men would choose illegal child pornography
given the abundance of legal pornography that depicts adults.
Thus, an undifferentiated group of offenders against children
would have a lower average pedophilic index than would a group
of child pornography offenders. Another possible explanation for
the difference between child pornography offenders and offenders
Figure 2. Maximum phallometric responses to child stimuli and to adult stimuli by child pornography
offenders, offenders against children, offenders against adults, and general sexology patients.
CHILD PORNOGRAPHY AND PEDOPHILIA
against children is that the child pornography offenders were less
likely to attempt to suppress their responses to stimuli depicting
children (or were less successful in suppressing such responses).
However, there is no a priori reason that the two groups of men
would differ in motivation or ability to suppress sexual arousal to
Our results have implications for both clinical and theoretical
work on pedophilia because they suggest that child pornography
offending has diagnostic significance and may be particularly
helpful in circumstances in which the person denies a sexual
interest in prepubescent children, or has no documented history of
sexual behavior involving children, or in which phallometric test
results are unavailable. Whether child pornography offending is
associated with a different prognosis than are other indicators of
pedophilic interests, such as its relative ability to predict sexual
recidivism, remains to be determined.
This study had several limitations. First, the study participants
were referred to the Kurt Freund Laboratory for a sexological
assessment because of clinical or legal concerns about their sexual
interests or behavior, so there may have been an ascertainment bias
that makes our sample less representative of child pornography
users in general. Second, there was a significant difference in
referral source across the groups examined in this study. Perhaps
reflecting this difference in referral source, 43% of the 100 child
pornography offenders included in this study had been charged
with a sexual offense involving a child victim, compared with
unpublished data that suggest that approximately a third of child
pornography offenders have a criminal record of sexual offenses
involving children (Federal Bureau of Investigation, 2002; Perrien,
Hernandez, Gallop, & Steinour, 2000; R. Smith, personal commu-
nication, July 20, 2000, as cited in Klain, Davies, & Hicks, 2001).
In contrast, Seto and Eke (2005) found that 24% of their sample of
201 child pornography offenders had a prior contact sexual offense
history. It would be very interesting to determine whether child
pornography possession is still a valid indicator of pedophilia in a
nonclinical and nonforensic sample. Although such research would
be more difficult to conduct, studies that could assure participants
of their confidentiality (e.g., using a Certificate of Confidentiality
provided by the National Institutes of Health in the United States
or using anonymous responses to Internet surveys globally) would
help elucidate the relationships between child pornography pos-
session, sexual interests, and sexual behavior.
Finally, although we were able to identify participants who were
charged for child pornography offenses, we did not have sufficient
information in the clinical file about the nature and extent of their
child pornography to examine whether specific types of content
were related to sexual history or phallometric test results. For
example, individuals who collect pornography depicting only girls
might be less likely to commit sexual offenses against boys or to
show sexual arousal to boys in the laboratory. Given the positive
relationships between sexual arousal to children and having mul-
tiple child victims, boy victims, and younger child victims (Seto &
Lalumie`re, 2001; Seto, Murphy, Page, & Ennis, 2003), and other
research demonstrating that these same victim characteristics pre-
Figure 3. Average pedophilic indices for child pornography offenders without a history of sexual offenses
against child victims, child pornography offenders with a history of offenses against child victims, offenders
against children, offenders against adults, and general sexology patients.
SETO, CANTOR, AND BLANCHARD
dict subsequent offending (Seto, Harris, Rice, & Barbaree, 2004),
one could predict greater pedophilic arousal—and a greater like-
lihood of subsequent sexual offenses against children—among
individuals who possess more child pornography content, pornog-
raphy depicting boys, and pornography depicting very young chil-
dren. We are now beginning a research project designed to test this
Abel, G. G., Huffman, J., Warberg, B., & Holland, C. L. (1998). Visual
reaction time and plethysmography as measures of sexual interest in
child molesters. Sexual Abuse: A Journal of Research and Treatment,
American Psychiatric Association. (2000). Diagnostic and statistical man-
ual of mental disorders (4th ed.). Washington, DC: Author.
Blanchard, R., Klassen, P., Dickey, R., Kuban, M. E., & Blak, T. (2001).
Sensitivity and specificity of the phallometric test for pedophilia in
nonadmitting sex offenders. Psychological Assessment, 13, 118 –126.
Cantor, J. M., Blanchard, R., Christensen, B. K., Dickey, R., Klassen, P. E.,
Beckstead, A. L., et al. (2004). Intelligence, memory, and handedness in
pedophilia. Neuropsychology, 18, 3–14.
Federal Bureau of Investigation. (2002, March 18). Operation Candyman
press release. Retrieved July 30, 2003, from http://www.fbi.gov/pressrel/
Finkelhor, D., & Ormrod, R. (2004, December). Child pornography:
Patterns from NIBRS (Juvenile Justice Bulletin NCJ 204911). Washing-
ton, DC: U. S. Department of Justice, Office of Justice Programs, Office
of Juvenile Justice and Delinquency Prevention.
Freund, K., & Blanchard, R. (1989). Phallometric diagnosis of pedophilia.
Journal of Consulting and Clinical Psychology, 57, 100 –105.
Freund, K., & Watson, R. (1991). Assessment of the sensitivity and
specificity of a phallometric test: An update of phallometric diagnosis of
pedophilia. Psychological Assessment, 3, 254 –260.
Galbreath, N. W., Berlin, F. S., & Sawyer, D. (2002). Paraphilias and the
Internet. In A. Cooper (Ed.), Sex and the Internet: A guidebook for
clinicians (pp. 187–205). Philadelphia: Brunner-Routledge.
Hanson, R. K., & Bussie`re, M. T. (1998). Predicting relapse: A meta-
analysis of sexual offender recidivism studies. Journal of Consulting and
Clinical Psychology, 66, 348 –362.
Harris, G. T., Rice, M. E., Quinsey, V. L., & Chaplin, T. C. (1996).
Viewing time as a measure of sexual interest among child molesters and
normal heterosexual men. Behaviour Research & Therapy, 34, 389 –394.
Harris, G. T., Rice, M. E., Quinsey, V. L., Chaplin, T. C., & Earls, C.
(1992). Maximizing the discriminant validity of phallometric assessment
data. Psychological Assessment, 4, 502–511.
Howes, R. J. (1995). A survey of plethysmographic assessment in North
America. Sexual Abuse: A Journal of Research and Treatment, 7, 9 –24.
Howitt, D. (1995). Pornography and the paedophile: Is it criminogenic?
British Journal of Medical Psychology, 68, 15–27.
Jenkins, P. (1998). Moral panic: Changing concepts of the child molester
in modern America. New Haven, CT: Yale University Press.
Jenkins, P. (2001). Beyond tolerance: Child pornography on the Internet.
New York: New York University Press.
Klain, E. J., Davies, H. J., & Hicks, M. A. (2001). Child pornography:
The criminal-justice-system response (Report No. NC81). Retrieved
February 3, 2006, from http://www.missingkids.com/en_US/publications/
Perrien, M., Hernandez, A., Gallop, C., & Steinour, K. (2000, November).
Admissions of undetected contact sexual offenses by participants in the
Federal Bureau of Prisons’ sex offender treatment program. Poster
presented at the 19th Annual Conference of the Association for the
Treatment of Sexual Abusers, San Diego, CA.
Quayle, E., & Taylor, M. (2002). Child pornography and the Internet:
Perpetuating a cycle of abuse. Deviant Behavior, 23, 331–361.
Seto, M. C., & Eke, A. W. (2005). The criminal histories and later
offending of child pornography offenders. Sexual Abuse: A Journal of
Research and Treatment, 17, 201–210.
Seto, M. C., Harris, G. T., Rice, M. E., & Barbaree, H. E. (2004). The
Screening Scale for Pedophilic Interests and recidivism among adult sex
offenders with child victims. Archives of Sexual Behavior, 33, 455– 466.
Seto, M. C., & Lalumie`re, M. L. (2001). A brief screening scale to identify
pedophilic interests among child molesters. Sexual Abuse: A Journal of
Research and Treatment, 13, 15–25.
Seto, M. C., Lalumie`re, M. L., & Blanchard, R. (2000). The discriminative
validity of a phallometric test for pedophilic interests among adolescent
sex offenders against children. Psychological Assessment, 12, 319 –327.
Seto, M. C., Lalumie`re, M. L., & Kuban, M. (1999). The sexual prefer-
ences of incest offenders. Journal of Abnormal Psychology, 108, 267–
Seto, M. C., Maric, A., & Barbaree, H. E. (2001). The role of pornography
in the etiology of sexual aggression. Aggression and Violent Behavior, 6,
Seto, M. C., Murphy, W. D., Page, J., & Ennis, L. (2003). Detecting
anomalous sexual interests among juvenile sex offenders. Annals of the
New York Academy of Sciences, 989, 118 –130.
Received August 27, 2004
Revision received July 28, 2005
Accepted July 29, 2005 䡲
CHILD PORNOGRAPHY AND PEDOPHILIA