The relationship between child pornography offending and pedophilia is sufficiently robust that child pornography use has been included as specific behavioral evidence in the proposed revision of the psychiatric diagnostic criteria for pedophilia, defined clinically as "persistent sexual attraction to prepubescent children" (American Psychiatric Association, 2013; Seto, 2010).
However, pedophilia is not the sole motivation for Internet offending involving children; that is, not all child pornography offenders show a sexual preference for children over adults.
This has been demonstrated in a recent study showing that the majority of Canadian child pornography offenders assessed at a sexual behavior clinic showed more sexual arousal (assessed through penile plethysmography responses in the laboratory) to children than to adults, and in fact show a stronger relative response than do offenders with contact victims (Seto, Cantor, & Blanchard, 2006).
Whatever the explanations for this increasing demand, it is clear that the number of potential Internet offending investigations already greatly exceeds law enforcement resources. Many law enforcement agencies are still dealing with a backlog of cases arising from Operation Avalanche (an investigation that began after the discovery of Landslide Productions in Texas and its large database of members purchasing access to child pornography Web sites) and other, more recent international police operations that have identified very large numbers of online offending suspects.For example, two programs (Fairplay and Roundup) have identified millions of computers involved in peer-to-peer sharing of child pornography files in the United States (U. Although more resources are being devoted to peer-to-peer investigations, many police investigators continue to conduct proactive, undercover investigationsin which they pretend to be a minor onlinein anticipation of solicitation attempts by adults (Mitchell, Wolak, & Finkelhor, 2005; Briggs, Simon, & Simonsen, 2011).Although resources for law enforcement in this area are increasing, the reality is that only some cases will be fully investigated and prosecuted.The latter group, in contrast, engages in online activities to arrange real-world meetings; their online activity is more directed toward meeting offline and shorter in duration than the online interactions of fantasy-driven offenders.Briggs, Simon, and Simonsen (2011) identified 30 offenders who were considered to be contact driven and 21 who were deemed to be fantasy driven.Other studies have also demonstrated a link between sexual interest in children and child pornography use through self-report surveys (e.g., Buschman et al., 2010; Riegel, 2004).