Board Thread:Questions and Answers/@comment-95817-20150812154044/@comment-61022-20150812173251

The age of Sam during all those periods is subjective, and is a matter of interpretation.

As for Gideon, the fact that he is Sam's older brother and ergo must have been there while Sam was raising his siblings is assumptive and not the only assumption you could form.

One explanation could be that because Sam had his mind tinkered with by the Red Skull using the Cosmic Cube, his recollections might be spotty or inaccurate at times. (especially on the age he was when his father died)

That aside, I would assume that perhaps Gideon wasn't living at home during the period that Sam was looking after his siblings. Also, characters sometimes have a selective memory (or at least their writers do), you could speculate that Gideon and Sam don't get along that Sam omits him from any story.

Or one more possibility is perhaps Gideon is the son of Paul from an earlier marriage. Not entirely impossible, and could not have been mentioned at this point because it hasn't come up in the narrative of a story.