I'm going to finish with you, Dr. Roberts, although I want to come back to Dr. Malamuth with one question.
You've spoken about the ethical issues involved in research. Obviously, we can't take a control group of children and expose them to violent and degrading pornography and follow them for a few years, as you've pointed out. Can we ever prove with scientific certainty what the impact of violent, degrading pornography is on children, given that limitation?