Comment by metalcrow
https://en.wikipedia.org/wiki/Relationship_between_child_por... is a good starting link on this. When i last checked, there were maybe 5 studies total (imagine how hard it is to get those approved by the ethics committees), all of which found different results, some totally the opposite of each other.
Then again, it already seems clear that violent video games do not cause violence, and access to pornography does not increase sexual violence, so this case being the opposite would be unusual.
The few studies on "video games cause violence" I've seen have been extremely limited in scope. They're too concerned with short-term frequency of playing particular games, or desire to play them. They're not concerned enough with the influence of being quite familiar with such games, or how cultural prevalence of such games normalizes thoughts of certain behaviors and shifts the Overton window. There are also selection bias problems. I'd expect media and games to more greatly affect people already psychologically unstable or on the criminal fringe... not people likely to be study participants.
Studies on sexual violence and changes in that over time have even more problems, for example how difficult it is to get average people to report accurately about their private relationships. Those people likely to volunteer accurate information are not necessarily representative.