Is Jack Amys Baby?
The one problem being over this side of the atlantic is that we get the episode later! Sorry if this has been covered but could Jack be Amys baby.
He is about the right age
I think Christian is on the island and could be the father of the baby and not Horace
If the baby (jack) was the first baby born on the island it could explain a lot of why Jack is very special
Another poster with a theory that losties could not go back in time to a period where they already were i.e. younger self could explain why jack jumped to a period 3 years later than Sawyer & co. Maybe Amy, Christian and baby Jack left