The Need for Children
My theory is that the vaccine is made on the island, and that is one of the reasons they are on that specific island. I'm wondering if they have to grow the vaccine in the children, but cannot extract whatever they need from the children until they are older. Not only do they want babies, but they also took Walt, and the children from the tail section. So it seems that whatever they wanted Aaron and Alex for, it also works on children who are older.
Luring People to the Island
There is definitely a force luring people to the island. Danielle Rousseau is not there by chance, and neither is Claire. For a while I've believed that the island chose people to bring to the island, that includes people on the plane, and people that were there before the plane crash. Now I'm starting to wonder if it's the island that is luring people, or, if it's the Dharma Initiative. The people who work for the initiative seem to be very powerful.It makes sense that the Dharma people would lure people with babies or children, but why crash an entire flight? And how did they know that anyone would survive? And was everyone on the plane "chosen", even those that didn't survive the crash?
Could it be that the Dharma people were looking for certain types of people, and one led to another, which led to another, thereby explaining why the survivors all seem to be interconnected? That seem pretty far-fetched, but possible.
It seems more likely that there is more than one force. Perhaps there is an island force and a Dharma force, but if so, than how come the island force doesn't overcome the Dharma force?

