Child Pornography Defences
There are three categories of statutory defences. All the defences should be “liberally construed”.
R v Sharpe, 2001 SCC 2 (CanLII),  1 SCR 45 at paras 60, 73
Reasonable Belief of Age
In an offence for making child pornography under s. 163.1(2), the accused may not rely upon a mistaken belief of age unless reasonable steps are taken.
(5) It is not a defence to a charge under subsection (2) in respect of a visual representation that the accused believed that a person shown in the representation that is alleged to constitute child pornography was or was depicted as being eighteen years of age or more unless the accused took all reasonable steps to ascertain the age of that person and took all reasonable steps to ensure that, where the person was eighteen years of age or more, the representation did not depict that person as being under the age of eighteen years.
1993, c. 46, s. 2; 2002, c. 13, s. 5; 2005, c. 32, s. 7.
Public Good Defence
There is an exception where the otherwise criminal conduct is for an enumerated public good and does not pose an undue risk of harm to persons under the age of 18. Section 163.1(6):
(6) No person shall be convicted of an offence under this section if the act that is alleged to constitute the offence
- (a) has a legitimate purpose related to the administration of justice or to science, medicine, education or art; and
- (b) does not pose an undue risk of harm to persons under the age of eighteen years.
1993, c. 46, s. 2; 2002, c. 13, s. 5; 2005, c. 32, s. 7.
This statutory defence was created in 2004. Prior to that there was a common law defence for possession for the "public good". The public good was defined as "necessary or advantageous to religion or morality, to the administration of justice, the pursuit of science, literature, or art, or other objects of general interest". This was found to include possession "by people in the justice system for purposes associated with prosecution, by researchers studying the effects of exposure to child pornography, and by those in possession of works addressing the political or philosophical aspects of child pornography"
The defence set out in s.163.1(6) involves two elements, but of which must be independently satisfied.
First, the court must consider whether there is any doubt that the accused subjectively had good faith reason for possessing child pornography for the reasons listed (administration of justice or to science, medicine, education or art). It must also determine whether, "based on all of the circumstances, a reasonable person would conclude that (1) there is an objective connection between the accused’s actions and his or her purpose, and (2) there is an objective relationship between his or her purpose and one of the protected activities (administration of justice, science, medicine, education or art)."
The test has been articulated as requiring consideration of: 
- whether the accused "had a genuine, good faith reason for dealing with the child pornography in question in the manner they did?"
- whether the reasons are listed in 163.1(6)
- whether "the accused’s actions objectively connected to his or her stated reason for dealing with the child pornography?"
- if so, whether "there [is] an objective connection between that stated purpose and one of the protected activities in subsection (6)?"
- if all the answers above are affirmative, whether the accused’s actions poses a risk to persons under 18, which involves considering:
- whether the risk is "significant" (more than "trivial or passing");
- whether the risk is “objectively ascertainable” (ie. risk is clear to the reasonable person based on commonly-available information).
"Education" can include "the education that parents may want to impart to their children in specific circumstances”, which can encompass a father holding onto a discovered child pornographic video created by the daughter in anticipation that the daughter would voluntarily admit her doings to her mother.
The Crown obligation to provide disclosure of child pornographic materials will be protected under s. 163.1(6) as it relates to the administration of justice.
Harm to Persons
The harm to be considered includes physical, psychological, or both.
The offence of Corrupting Morals has a "public good" defence as well.
- R v Sharpe, 2001 SCC 2 (CanLII),  1 SCR 45 at para 70
- Sharpe at para 70
- R v Katigbak, 2011 SCC 48 (CanLII) at para 56
- R v Katigbak, at paras 57, 58
- Katigbak at para 60
R v Jeffrey, 2012 SKPC 12 (CanLII) at para 31
- see R.L. v R., 2009 QCCA 546 (CanLII),  R.J.Q. 669 (Que.C.A.), esp. para 53
- R v Blencowe,  OJ No 3619 (ON SC), 1997 CanLII 12287 (ON SC)
Katigbak, at para 66-67
Private Use Defence
It is not necessary for the crown to establish intentional downloading to establish possession. The accused must have 1) knowledge of the character of the object, 2) knowingly put or keeps the object in a places and 3) intends to ahve the object in the place for his or another person's benefit.
Where there is evidence of intentional downloading, the Crown can rely on the presumption that "one intends the consequences of one's actions".
In order to rely upon inadvertence the defence must adduce some evidence supporting this, rather than simply speculating.
The number of CP files present on the computer will weigh against the conclusion of accidental downloading. Larger numbers will in fact permit the inference of "actively searching and downloading files". Likewise, the manner in which the files were stored will also contribute to rebutting the conclusion as well as the number of places in which the pornography was saved.
The presence of search terms that relate to child pornography is evidence that can rebut the claims of accidental download.
Identical creation and access dates can be consistent with inadvertent download.
R v Morelli, 2010 SCC 8 (CanLII) at paras 15 to 38
R v Missions 2005 NSCA 82 (CanLII) at para 21
R v Braudy, 2009 CanLII 2491 (ON SC) at para 55
R v Jenner 2005 MBCA 44 (CanLII), (2005), 195 CCC (3d) 364 at para 21 (Man. C.A.)
Missions at para 21
R v Pelich, 2012 ONSC 3611 (CanLII) at para 72
e.g. R v Smith, 2008 CanLII 59107 (ON SC),  O.J. No. 4558 (S.C.) at para 28 - judge dismisses first-time accidental download claim
e.g. Smith at para 28
Missions at para 22, 27
e.g. R v Gilbert, 2015 NSSC 69 (CanLII)
R v Clarke, 2016 CanLII 874 (NLPC)
- R v Garbett, 2010 ONSC 2762 (CanLII) at para 64