Would still not be legal in the US.
Section 2256 of Title 18, United States Code, "defines child pornography as any visual depiction of sexually explicit conduct involving a minor (someone under 18 years of age). Visual depictions include photographs, videos, digital or computer generated images indistinguishable from an actual minor, and images created, adapted, or modified, but appear to depict an identifiable, actual minor. "
So even if no real-life child was involved, it would still be illegal to depict.
If I understand this correctly, this means that the DA would have to have an actual child that they could produce that looks like the computer generated child.
Maybe they could do it maybe not.