kingjames

Question: Since the probability of having three children is greater than the probability of having two children, shouldn't Marty (as the youngest) disappear from the photograph first rather than last?

kingjames

Chosen answer: Probability has nothing to do with it. The changes in the timeline are rippling out from the initial point of disruption. As Marty's brother and sister were born before him, their respective births are closer to the point where the alteration happened. As such, they're erased from the timeline first, so they fade out before he does.

Tailkinker