Okay, so I've been thinking about this for a while now. Back in series 1, whilst still pregnant, Claire comments that she hasn't felt her baby kick since the crash. Shortly after this she swallows that oyester thing (sorry I don't know what its called) that Jin gives her. After eating this the baby suddenly starts kicking and becomes active. My theory is that Aaron died in the womb and was resurrected similar to Locke. Why didn't it happen straight away you may be asking. Up until that point Claire had not consumed anything from the Island. The water and food packs from 815 is all she had eaten upto that point. When she consumed something from the Island this was enough to revive the baby. My theory is that contact with the Island (or things from it) is what cures and/or revives certain "special" individuals. By this theory it is understandable how Ben was able to cure Juliet's sister's cancer. Things from the island may still retain their healing properties when taken back to the rest of the world. What do you think???