Board Thread:General Discussion/@comment-4115284-20150428133857/@comment-26072045-20150430162813

BoomCipher wrote: There are only two choices before us. Stan is Gruncle. Grand Uncle. That means that either the Author is Dipper and Mabel's Grandfather, or there is another Skywalker.... Sibling! I meant sibling!!

And he said "my brother" which implies that the sibling is a woman. Had he said "Your Grandfather" I think Mabel would have fainted! But the AMA does make it sound like it's a brother...

Untrue. For one thing I only have brothers. If I introduced one of them I would say "this is my brother" not "this is my sibling." Also there is not only two choices. There is a theory that Stan is actually their grandfather and it makes sense too. Here is a link. Personally I think that this is true. It would be really cool if it is.