Vitally important as it is to protect children from sexual predators (which of course includes the market for child pornography), I'm concerned that including general child abuse in this will both silence child abuse survivors and make it more difficult for abused children to ask for help or advise anonymously online. I don't think differences in English usage across the world should override this.

There's a lot of variations on "realistic human 3D models are difficult and expensive, therefor CGI software is unlikely to replace photography anytime soon" in the posts above. Wanted to point out: DAZStudio4Pro is currently free (along with its companion programs Bryce and Hexagon) and comes with an androgynous free human figure (called Genesis) that can be easily worked into a wide variety of realistic men, women, children, aliens, and demons:
http://www.daz3d.com/i/products/daz_studio?

The site (and several others) sell presets to easily make Genesis into various realistic characters, also lots of 3D clothes, props, and scenery -- but, like Blender, DAZStudio4Pro is free (unlike Blender it's not open-source, has been paid software in the past, and almost certainly will be again).

Plenty of examples on the site's forums of extremely photo-realistic 3D human renders, too: http://forum.daz3d.com/ , try starting with http://forum.daz3d.com/viewtopic.php?t=189377 and http://forum.daz3d.com/viewtopic.php?t=165191