Porn involving consenting adult individuals is a 1st amendment right-- for the adults viewing it, the adults selling it, and possibly even the adults making it. And it's something many people are very enthusiastic about loving.
So... what happens when the porn involves consenting adults who either look, or have been digitally altered to look, much younger than the age of consent? A stickier situation-- if only because its an ickier situation.
Right now, I'm researching some issues involving the 1st amendment. One of the cases I ran across is Ashcroft v. The Free Speech Coalition, 535 US 234. The case involves a statute that bans depictions of minors engaged in sexual situations-- even if no actual minors are involved in the making.
A gut, visceral reaction might be that this is not ok, and that people who want to wank to images that appear to be of teens or kids shouldn't get to. The Supreme Court disagrees. They talk about the fact that this statute would also inhibit artistic depictions, like Romeo and Juliet, or American Beauty, or Traffic... or Gossip Girl. But limiting the discussion to classy movies/plays takes the easy way out-- and ignores the ick factor of porn involving people who look like minors.
The idea of youth as beauty and as the sexual peak is pervasive in modern society. That's a given, I'd say. People counted down to the 18th birthdays of the Olsen twins and Emma Watson; adults get "crushes" on the characters of Gossip Girl and whatever else is on TV these days. So... it's almost a given that at least some people are seeing in their heads women or men who play the roles of teens on TV shows, if not actual teens. So, if we as a society are ok with deceptions of teenage sexuality in our entertainment... and if watching/making virtual teen sex with adult actors or computer modelling is a first amendment right... then is virtual minor porn... good? bad? indifferent?
Child porn-- or teen porn-- is bad because it involves a lack of consent and, unless its homemade porn by a couple teens, sexual abuse. Even if teens say they consent, they legally can't--hence a lot of the lawsuits surrounding the Girls Gone Wild franchise. In America, at least, there's a general moral approbation against minors and sex. So, while watching virtual-minor porn is a legal right-- is it morally right? I'm not entirely sure, to be honest. But I'm also not sure that it's any worse than porn that shows adults as adults. I don't think that masturbation, or watching porn are bad things. Yes, I know porn can be exploitative, and that it can lead to negative attitudes towards women, a sense of entitlement, and confusion over what to really do in the bedroom. But the people that are really effected that way are going to get similar messages from the rest of society, even without the overt sexuality. And watching porn is done by... I'm sure more than half the population. Hell, I'm sure more than half the female population watches porn-- though as least from anecdotal evidence (which yes, means approximately nothing) they tend to like different kinds.
And people like all kinds of porn! I don't have a problem with people who want to watch S/M porn, or doctor/patient, or porn where the characters seem to have questionable consent, or tentacle porn, or... well, you get the point. Other people's kinks don't bother me-- especially when they stay in the realm of fantasy. So what's the harm with someone who wants to jack off to it? Yeah, the thought is on the gross side. But so are a lot of things-- to a lot of people. And maybe your imagination would be on the sick side to someone else. You never know.