Depends on what kinds of visuals you need, Danny... which then will move this conversation to the Presentation forum in all likelihood...
You can place 2D cutouts, if you just want the outlines of children... by basically making a Morph that traces the outline of a child (or existing child-linework that you find on the internet). Stand these around as needed to appear in any view. Make them an opaque glass material to show them as children ghosts in renderings.
You can place 2D masked images of children by making a special version of the 2D bitmap tree/person object... but these will only look normal in renderings.
A 3D GDL child will look pretty much horrible in any elevation/etc - just as the 3D people do... too many contour lines. Even rendered, they will be polygonal.
Rendering in Artlantis or other software can give smoother results, and Abvent does have children for download.
And, of course, there's the post-production Photoshop insertion of masked images of children...
All depends on what you need to generate, what software you have available, and the time you want to put in / skill set...
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