Originally posted by: ADigitalMan
Not saying Shorty is supposed to be Indy's son on a genetic level, but he was more of an adoptive son, and Spielberg could have gone a dozen good directions with that. Instead we've now got: "Here's Indy's Kid. Accept it."

Some of us don't see it that way though. I never saw Short Round as anything more than a sidekick. No more, no less. Believing Shia is Indy's son doesn't require that much suspension of disbelief. We're pretty sure Indy and Marion had a relationship of some sort (it's alluded to in one of her lines at the start of Raiders), so there's no reason to believe they couldn't have had a son out of that relationship. Hell, there's no reason a son couldn't have come out of their relationship between Raiders and Last Crusade. Maybe he went off on an adventure of some sort and just disappeared for a while, so she never bothered to tell him about their son. Even in the beginning of Raiders, she didn't seem like someone that wanted him around, so she'd have no reason to tell him.

The point is, shit happens all the time between people and they don't find out things they should until years later. Assuming Lucas isn't writing the script (is he?) we have no reason to believe the explanation will be as simple as Shia: "I'm your son" Indy: "Oh...ok...well, let's go get the bad guys"