Huh? Why? If no children are hurt in the process what's the issue? You're just against it because it, quite understandably of course, makes you feel icky. But at that point you are protecting your feelings, not actual living children. Should people be arrested for hentai that has kids in it as well?
I mean sure, let's judge the fuck out of people that would jerk off to kiddie hentai or fuck a childbot or whatever. But make it illegal? If so, at least admit its only to protect your feelings at the expense of freedom however vulgar that freedom might be.
"Children" is not a universally agreed upon category. In one US state the age of consent might be 16, in the next it could be 18. Does a 17 year old magically lose the ability to consent to sex upon crossing the border from the first state to the other? In Europe some countries have the age of consent as low as 15, are European kids biologically more capable of consent?
People seem to think that this appeal to "consent" and the legal definitions around it are some bullet proof moral argument but they're not, the legal definitions are often arbitrary. The sanctity of children and childhood is a relatively recent phenomenon and its not even a universal one in the world today. A 15 year old Afghan boy might very well be already married, a property owner, and know his way around a gun. Compare him to that 30 year old guy in NYC who got kicked out of parent's house for being a fucking bum. Who is really more mature? Who is really more capable of consent?