I have thought about this in depth and it seems that the best course of action is go leave the toilet seat up in public toilets. At home, down, yes, I don't mean that.
Allow me to explain. When you flush, little bits of water from your bidness gets thrown into the air. These small particles are thrown onto your toothbrush and any other exposed area. To me, it seems the best course of action, to avoid anything unsavory falling onto the toilet seat, you'd leave it up. This would create a shield that would deflect any spray from the toilet while also protecting the seat portion that you sit on from anything that might fall from above (dead skin, hair, boogers).
What do you think? Am I on to something or is this a load of crap?