I'm interested in why Amy could have a baby and "in the future" women couldn't. Is it related in some way to the number of people who can be on the island at one time? If that number falls below a certain level, the island reincarnates them or causes a boat or plane to crash? Is that why the oceanic 816 survivors are split between times, now that the Ajira survivors are in the "present" and most of the Oceanic are either dead or in the past. This could explain why the oceanic 6 may be split in time, too.