The pattern is obviously well established.
Only someone who is interested in having sex with children would be interested in watching child porn.
As far as behavioral studies goes. People indulging in any such deviant behavior are proven to become more sick in the head. Pedophiles, rapists, murderers.
It will also lead to normalizing pedophilia. Just like how normalizing homosexuality and transing children led to an explosion of homosexuality and child grooming.