Mothers gave birth safely before the incident. ("LaFleur") Over-reactive healing kills pregnant mothers. ("The Other Woman") The source contains life, so's likely behind the Island's healing properties. ("Across the Sea") The incident released the source's electromagnetism. ("The Incident, Parts 1 & 2")
Wow, glad we cleared up the pregnancy mystery. But this also changes our understanding of the Island's healing properties. Are there any examples of mystical healing before the Incident?
Even more intriguing, did the Island heal anyone post-Season 2, once the Swan stopped discharging EM every 108 minutes? I know Richard said the island would heal Locke's bullet wound, but we had no time to see if it did. ("Because You Left") And Locke and Rose's didn't get sick again, but if the island really healed Locke's spine and killed Rose's cancer cells, their illnesses wouldn't recur right after the EM left.