Well, I think you can get away with calling the hematology (squee!!!) and reproductive cells adorable. Nobody will hate on a plush ovum the way they might a life threatening disease. I showed DS a few and his favourites were the neutrophil and plasma cells, though he did appreciate the plague and, curiously, e-coli.

For a laugh, let's just imagine the ways the line, "he did appreciate the plague" could be misconstrued. I love this forum.
_________________________
Success is not final, failure is not fatal: it is the courage to continue that counts.