David Bernstein at the Volokh Conspiracy sniffs it right:  This story from the Washington Times is problematic on so many levels:

"Imagery definitely affects children," said Dr. Sharon Cooper, a forensic pediatrician and faculty member at the University of North Carolina Chapel Hill School of Medicine. "Adult pornography is a good example of giving children unhealthy sexual images."

Pornography normalizes sexual harm, Dr. Cooper said. It shows children a lack of any kind of emotional commitment or relationship between two consensual partners, shows unprotected sexual contact and visual examples often of violent rape....

Children are very vulnerable as compared to adults because of the presence of mirror neurons in the brain, Dr. Cooper said. Mirror neurons are part of the brain that convince us that when we see something we are actually experiencing it.

Of course there are lots of reasons to be concerned about the ready access that many children have to pornography thanks to the internet.  And undoubtedly some of that access causes unhealthily values among developing teens about sex and relationships.  But to say that pornography in and of itself normalizes sexual harm begs the question how it does so.  To say that it occurs through some neurological component that's not well understood but presumably is broadly implicated in everyday living falsely implies a causative pathway.  This type of reasoning is common these days, with all sorts of complex human behaviors and experiences (e.g., learning) supposedly understood by the activation of neuronal tissue.  Yet to describe a physical process such as neuronal activation does little to explain why people experience, learn, or do what they do in everyday life.    It's a vapid simplification of the human experience and the mind.