We've established that chakra element is hereditary (I.e. Sasuke got fire from his parents, etc.). Is there any precedent for what happens when parents with different elements have a kid? Does one element "win" and become the one that the child has, or does the child get both?
Let's first off state bloodline limits.
Bloodline limits come with perks like Wood and Ice elements (Yamato and Haku). This suggests that there is indeed a chance (Since it's not for everyone, just like the sharingan and byakugan) they will inherit it from their parents.
It doesn't seem like anyone outside the clans have the blood limit abilities, so we will assume that even when someone does not posses for example, Wood elements, they might still be carriers and carry the ability on to their children.
However, they do seem to pass on elements within clans. The Uchiha specializes in Fire, Uzumaki in Wind, and so on.
It is quite safe to assume that you inherit the talent for your chakra element type.
Anyone can learn any chakra element type given enough practice. Even though this won't easily become better than their main chakra element type, it could still be passed on to their children more naturally.
Furthermore, it's probably a lot like bloodtypes in real life. Tho there are technically rules, every human can get a random blood type instead of what their parents got. if not, we would all have the same blood types in the end! I believe this is also how the elements work. It's a game of chance between which parent has the stronger genes.
- I've been a proper fan for 10 years now and am rewatching + reading it for the 9th time or so.
- http://naruto.wikia.com/wiki/Chakra This webpage explains how ninjas can learn chakra types besides their natural affinity.
Other than that, this is all speculation. There is no proof of what I said and there is no explanation from Kishimoto relating to this. All my speculation is based on how I have learned the anime and manga.
Uchiha are already affiliated with fire and can learn other elements by practice to help answer this even more it is more or less possiable Naruto character's are more likely born with elements though birthday's like Naruto Oct 10 1996 he has wind and he is a Libra but it also goes by one's clan blood line also so bit can be by both ways.