There have been a few blog posts that attempted to establish a pattern of previous Avatars' genders in order to extrapolate succeeding Avatars' genders, much like how the last one dealt with the gender of Korra's successor, a future Earth Avatar. While it is impossible to predict with certainty the gender of an Avatar based on algorithmic patterns, I believe that a key factor in gender identification could revolve around the aggression levels of the immediate predecessor.
I hypothesize that the higher an Avatar's sustained aggression in certain situations, the more likely the next Avatar would be male. Likewise, the more passive an Avatar is, the more likely the next Avatar would be female.
I base this theory on the fact that before Aang, the previous 5 Avatars alternated between males and females (3 males, 2 females). We don't know what the Unnamed fire Avatar's temperment was, but given the fact that his successor, Yangchen was female, he was likely a passive Avatar. Yangchen didn't hesitate to use force when necessary, as she explained in 3.19, likely giving rise to Kuruk after her death. Though Kuruk was a showoff (as seen in the Escape from the Spirit World game), he was more passive than aggressive, therefore Kyoshi became his successor. She was ruthless at times and didn't hesitate to kill, like she did to Chin, and developed the Dai Li. After her death, Roku took the mantle. He's tricky since he was virtually split between passive and aggressive. It shifted to the latter at times though, due to his animosity with Sozin as well as giving his full effort to save his people from a volcanic eruption (in vain though). Aang came after, and like a true Airbender, avoided fights in most situations and did not want to hurt anyone or anything except when he had to. Korra is now the Avatar, and judging from the trailer, she shows no hesitation in using her opposing bending art, Firebending, and is always starting fights. I think she also enjoys using Firebending based on the trailer.
So what do you guys think? Does this theory have merit? Entia non sunt multiplicanda praeter necessitatem 13:44, September 29, 2011 (UTC)