It is an affirmative defense to any prosecution under ORS 163.684, 163.686, 163.687 or 163.693 that the defendant, at the time of engaging in the conduct prohibited therein, did not know and did not have reason to know that the relevant sexually explicit conduct involved a child. [1985 c.557 §7; 1987 c.864 §13; 1991 c.664 §9; 1995 c.768 §7]
Oregon Legal Code