The latter 3 are not too interesting IMO, because porn and masturbation have been around for centuries, and whatever effects they've had have become part of society.
The first one might be an interesting one to consider. Of course this is assuming children get hold of the pornography at an earlier age than they should and continuously have easy access to it. And in my opinion, the only thing that occurs is that children will get desensitized to the typical types of sex early on, and when they reach the age where they will be participating, they will need or want more interesting, atypical, types of sex to fully enjoy themselves.
...whatever effects they've had have become part of society
Your comment seems to imply that the effects are complete. I'd disagree with that.
I'd say access to pornography has changed dramatically in recent years. Anyone with an internet connection can find porn in relative anonymity and I don't think we've seen the full effects of it yet.
children will get desensitized to the typical types of sex early on
As children become more sexually aware, they'll probably turn to the 'net to learn more. I suspect their expectations of what is 'normal' will be set by what they find there. I don't think it's just desensitisation that will take place.
It's gotten to the point where the porn will find you. Try surfing intensively across a range of sites for a couple of hours without running in to porn. All it takes is one link to an expired domain.
"Depictions of a sexual nature are as old as civilization (and possibly older, in the form of venus figurines and rock art),[2] but the concept of pornography as understood today did not exist until the Victorian era(1900s)" [1]
But my idea of "pornography" was simply depictions of sexual nature (which is centuries old as stated in Wikipedia)
The first one might be an interesting one to consider. Of course this is assuming children get hold of the pornography at an earlier age than they should and continuously have easy access to it. And in my opinion, the only thing that occurs is that children will get desensitized to the typical types of sex early on, and when they reach the age where they will be participating, they will need or want more interesting, atypical, types of sex to fully enjoy themselves.