The work of Cantor and colleagues has continued beyond the early study cited by jd.

http://www.slideshare.net/forVP/cantor-38137529

His version is that sampling prisoners on both ends cancels out the fact that the subject is Pedophilia in criminals, not Pedophilia among the law-abiding.

I commend you for understanding the basic claim, which is more than a lot of anti-Cantor commentators do.

Cantor would jump up and down in glee at the idea that he could study non-offending pedophiles. But he can't because we don't show up, and even if a few volunteered it would be a biased sample. Someone suggested the way these could be tested would be in some country with universal military conscription that required a PPG test of a random sample of the young men in a country. But it seems unlikely that's going to happen soon.

Science is constantly stuck with generalizing from imperfect experiments. There IS a leap of generalization to be made from the criminal to non-criminal population. But the job of someone who wants to object is to offer a theory (no experimental results required initially) as to why pedophile sex offenders would be less intelligent than non-pedophile sex offenders but that difference would not show up among the non-criminal. With such a theory and the means to test it, the scientific process could proceed.

For instance, "Pedophilia" has been observed in many other species. And by Cantorian standards we can generalize from those samples to humans so long as the non-Pedo control group are the same species.

Certainly pro-contact activists have cited other species. It is a weak form of evidence because other species are far more different from humans than sex offenders are from ordinary people. But when arguing for instance that greater human male aggression is innate rather than learned, findings from a wide range of closely related species that all show the same thing are highly relevant. In that case there is a control group in each species, namely females.

Never mind the obvious objection raised at BC that some crimes require a mind capable of great forethought, abstract thinking capacity and restraint ...

The control group is other men guilty of sex crimes, not other crimes more broadly.

My recollection of a post I made on BoyChat some time ago was this: There is plenty of opportunity for there to be different kinds of pedophiles, and the Cantor results could apply to some of them but not others. If you think you are a kind of pedophile that is not on average less intelligent than the population at large, no one can tell you you're wrong. Cantor said he found nothing to object to in that formulation.