I think that in the next ten years where prosthetics will become so advanced that they will be able to be controlled without conscious effort on the part of it’s wearer and that it will be impossible for anyone to know that the wearer is using a prosthetic limb due to it’s real life appearance and movement.
Prosthetics have moved from metal, un-lifelike looking implements to much more realistic looking limbs in the past 20 years or so. However I think that they have some more developments to go. I think that eventually science will enable people to re-grow their own limb, however in the meantime I think that the limbs will be controlled subconsciously from a patients brain in the way that one’s own limbs are currently controlled and that they will be able to be covered in a skin graft or similar material that will give it a more natural appearance. Robotics will have improved greatly that it will be possible to have a full range of movement.
Some work is already under way to develop these – with researchers at Brown University implanting a chip into a patients brain that enabled a paraplegic to be able to move her limbs(1).