i kind of got to thinking today about how little we know about aang's childhood. no one ever really cleared up how aang was discovered as the avatar. i mean, they couldn't have checked every baby, they might have been able to make a guess, based on the birth of babies around the same time as the death of the previous avatar, etc. but still, we don't know about aang's parents, his home life, and a bunch of other stuff.
so basically, i got to thinking today, is it possible aang had a brother or sister? at first i thought twin, but that would probably be kind of a stretch since aang probably would have been raised with him/her to some extent until the monks could be sure who was the avatar and stuff like that. but i was just thinking what would happen if aang did have a brother or sister? could they have had a son or daghter aang could meet? could they themselves still be alive?