So even though it hasn't been broadcast, you guys are familiar with my take on the Shadow Children/ Abos as far as their distinct speciation and reproductive cycle. I caught up with the podcast and one of the things that I think is implied somehow in the book, as impractical as it is, is that if the shadow children are originally from Earth, they are probably the fey changelings that once haunted earthen tales rather than standard human beings - and that the kind of evolution we are talking about to get the reduced Shadow Children is not generations but millennia. My take on their belief in their own humanity has been one of empathic telepathy: they can encounter the humans in space and begin to lose their own sense of identity in mind to mind contact. However, the idea that David has at the start of Fifth Head, if one were inclined to give it any credence, would suggest that the shadow children came long ago and evolved quite distinctly from the humans that will soon visit the planet again. As you know, I think of them as parasites and the second novella as a metaphor for a personal history in addition to the historical work it does. But the mechanism for such transportation makes a lot of assumptions about ancient Earth and interstellar travel, even if the Shadow Children were always somewhat ephemeral.