As I said above, though, you don't need to make a model that's specifically "for child porn" in order for it to be able to generate child porn. There are already probably plenty of models that know what children look like and also know what porn looks like, made simply by teaching a model about lots of diverse subjects that happened to include both of those subject areas in them. You can even make new models by merging two existing models together or by adding more training to an existing model, so you wouldn't even need to have those images be part of the same training run.
I obviously haven't ever tried generating child porn, but I fired up my local Stable Diffusion with the Cyberrealistic model and generated a toddler on the moon and a toddler riding a lion. I'm reasonably confident that the model wasn't literally trained with images of toddlers in space suits or toddlers riding large wild predators, it was trained on those concepts separately and was able to figure out for itself how to combine them. Notice how it was able to figure out that a toddler on the moon would be in a space suit and re-proportioned the space suit accordingly, and that a saddle used by a toddler would probably have handlebars (I'm guessing it has a bunch of images of toddlers riding ponies that it got that idea from).
