Cloning and such

I've been noticing more and more that Ishiguro likes to randomly drop these bombs in mid-sentence throughout his work.  We go through the first half of the book only knowing that the students are special and different in some way, but never know exactly why.  And then Ishiguro just slips into a random sentence that, oh hey, they're clones.  No big deal, right?  Is that the reason they can't have babies even if they wanted to?  For Kathy and her peers, wondering about or looking for their possibles must feel similar to an adopted child searching for his birth parents.  It must be terrifying.  On one hand, you have to be dying to know who they are, what they're like, in what ways you're like them.  But, on the other, it has to be absolutely terrifying!  They would have spent their whole lives wondering about these people and dreaming them up to be these kind of legends in their minds.  What if they, by chance, meet their model and are devastated by what they see?  "Our models were an irrelevance, a technical necessity for bringing us into the world, nothing more than that" (Ishiguro, 140).  The students try to act like they really don't care about who their models are, but deep down, they all do.