Porn is not unhealthy. In fact, I would say it is very healthy. Porn is what keeps married men from cheating. It's porn for a reason. Pure fantasy to satisfy that area of human instincts for both men and women. To deny and/or defy it is going against mother nature herself.
			
		
 
	 
 I think this really depends on the man.  
Following what CharlieBoy stated, I know quite a few fellows who have really distorted views of what a woman should look like and how she should perform in the bedroom as a result of a steady diet of pornography.  
I can't see how limiting porn is going against mother nature either, as I have yet to see a pair of breasts in such entertainment that do not deny and/or defy her.
~Sphinx
				
			 
			
		 
			
				
			
			
				You don't need eyes to see, you need vision.  ~Faithless, Reverence.