Critical review on 3D printing

I have heard about this not too long ago. Printing things in 3D is definitely a large step in technological advancement. I think this could be very cool to use in classrooms as a teacher. It would be much easier to get a hold of objects that cost a lot, or are in other cultures. It would also be cool for art teachers; just print off a blank object and have them paint it as they'd like. Even for science teachers that have to dissect animals. I always found this to be cruel, now they can just print one that is already dissected to show major organs. The dangerous side to this would be the whole gun aspect. If a child printed one of these off, there might be issues. Maybe they should install parental controls? Overall this is really cool and if expected to be in most households within 5 years... I cant imagine all the possibilities for this great invention!