Well, i attended some biology laboratories some years ago (i was attending a biology universitary course), and it was not so much disgusting, i immagine that knowing a bit of anathomy and a big deal of phisiology and isthology helped me a lot into focusing over the "biological" side of the issue and not getting overridden by disgust. I immagine that today (i switched to an history course after three years) a surgery operation would let me indifferent (no interest, no disgust...).