Effort underway to issue a retraction of study by M.C. Seto, R.K. Hanson & K.M. Babchishin
In any body of scientific research, of course, there is always that pesky outlier. In this case, there is one loner study that reached markedly different findings from the pack (and got a substantial amount of attention in the process). That article, based on convicted offenders at a federal prison in Butner, North Carolina, is regarded as an unreliable anomaly . Prisoners at the facility said they were coerced into falsely claiming that they had molested children under threat of being expelled from the treatment program and shipped off to more dangerous penitentiaries. Further, they were never informed that they were part of a research project, and did not give their consent (which if true would be a violation of the Nuremberg Code). Federal judges have been harshly critical of the study. Based on its multiple identified problems, there is even an effort underway  to get the Journal of Family Violence to issue a retraction.
[1: Study: 'Contact sexual offending by men with online sexual offenses' by M.C. Seto, R.K. Hanson & K.M. Babchishin; March 2011]
[2: by Richard Wollert & Alexander Skelton, see: richardwollert.com/pubs/Wollert_Skelton_Dubin_book_chapter.pdf]
source: Article ' Why are these men downloading child pornography? - ... And how much risk do they pose to a fearful public?' by Karen Franklin (PhD); forensicpsychologist.blogspot.nl/2017/05/why-are-these-men-downloading-child.html; forensicpsychologist.blogspot.nl; 21 May 2017