Short answer:
At the time the laws were made there was no empirical evidence that fantasy material was linked to child abuse. Instead, the laws were formed solely based on moral and potential for harm guiding principles.
Long answer
Because the laws are relatively new there is not a lot of research directed at fantasy material.
The following will be based on the 2017 PhD thesis of Hadeel Al-Alosi titled Fantasy Crime: The Criminalisation of Fantasy Material Under Australia’s Child Abuse Material Legislation. pdf of PhD available online.
Al-Alosi also has a book from 2019 available, but I do not possess it nor do I have access to it. The Criminalisation of Fantasy Material: Law and Sexually explicit representations of fictional characters. This book is likely to be a good source.
I am not in anyway an expert (I am not even an amateur), nor did I commit the time required to read the entire thesis. What I present is based on reading concluding and summary comments on individual chapters, as well as keyword skimming of the document.
On pp. 19, in regards to whether there is evidence that fantasy material can reduce incidences of real sexual offenses [the following paragraph has many references which I have not included, but those interested can look up the actual paragraph in the above link for further investigation]:
Conversely, others have questioned whether deviant sexual fantasies are a reliable predictor of future offending for sexual offenders. Some studies have indicatied that not all offenders who molest children experience sexual fantasies involving minors prior to their offense. Also, some suggest deviant fantasies may allow paedophiles to release sexual tension, which reduces the chances of paedophiles engaging in sex offending in real life. Given the inconsistencies in the research, the relationship between fantasy and child sex offending remains ambiguous.
On pp. 34
- Does the empirical evidence support these theoretical justifications?
It is necessary to examine the available empirical evidence to assess
whether any of the prevalent theories justify criminalisation. In
chapters 7 and 8, the literature reviewed is synthesised with the
theoretical justifications to answer this question. However, given the
limitations of the existing literature, this study also conducted
surveys and interviews with relevant individuals, seeking their views
as to whether the prohibition is justified. Therefore, the theories of
criminalisation are used as a tool for interpreting the evidence.
Where this is in reference to
- What are the possible theoretical rationales and justifications for
prohibiting, or not prohibiting, sexually explicit fictional
representations of minors?
Thus, chapters 7 and 8 are the places to look for empirical evidence.
Here is the conclusion to chapter 7
7.4 Concluding Remarks
The aim of this chapter was to assess the potential harms created by
fictional child pornography and determine whether the Harm Principle
can justify criminalisation. It was found that, even though there is
no conclusive empirical evidence such material causes harm, it is
reasonable to believe that fictional child pornography can negatively
affect viewers. The central role of fantasy in the aetiology of sex
offending has been well documented, highlighting that there is a
significant risk that fantasy incites child sexual abuse. While the
existing research is limited by its focus on serious child sex
offenders, it is clear fictional child pornography, like other types
of media, has the potential to desensitise viewers of all ages and
backgrounds. When desensitisation is taken into account, the harm of
fictional child pornography is sufficient to justify preventing its
dissemination. The Harm Principle, however, has its limits and cannot
support criminalising private possession of self-created works of the
imagination
From this conclusion there is (as stated by it) no conclusive empirical evidence that such material causes harm.
The conclusion to chapter 8 is
8.3 Concluding Remarks
This chapter firstly discussed whether prohibiting fictional child
pornography can be justified on the Offense Principle. It was found
that the Offense Principle would support prohibiting the widespread
dissemination of such material but not criminalising private
possession, accessing, or sharing of such material with willing
viewers. Provided there is no spiteful motive to cause offense to
others, the Offense Principle would only go so far as regulating
fictional child pornography to prevent unwitting exposure. The second
section of this chapter considered whether Legal Moralism supports
prohibition. As discussed, Devlin’s extreme Legal Moralism provides
the strongest theoretical basis for criminalising both dissemination
and private possession of fictional child pornography. Although Devlin
argued that the law should, as far as possible, respect individuals’
privacy, he emphasised that it is legitimate to criminalise certain
conduct if it is beyond the limits of tolerance. Whether fictional
child pornography crosses this limit is a question that needs to be
investigated through future research. A modest Legal Moralism can also
support prohibition, provided such material is considered objectively
wrong. While Moral Paternalism may support criminalisation, it is
questionable whether virtue can be coerced. Even though it is
relatively unproblematic to find that both Legal Moralism and Moral
Paternalism support criminalising fictional child pornography, legal
enforcement of morality is controversial in liberal societies. This is
reflected in the literature, as well as the survey findings.
From what I can distill from the thesis, it appears the arguments against fantasy material involving children comes down to morality arguments and unacceptable risk of harm.
Thus, my conclusions are that more research is needed. It does however appear certain that at the time the laws were made, there was no empirical evidence. Rather moral and potential for harm principles seem to have been precedence.
