Board Thread:Theories and Speculation/@comment-5012682-20150620162706/@comment-2140588-20150620175942

Legendary Super Saiya-Jin 4 wrote: @Omo I see, well even if Sasuke's main affinity is lightning. Due to being an Uchiha, he still inherited fire release naturally. So those two are his strongest natures. The issue with the Boruto thing though, is since we don't know Hinata's affinity, we can't use that as proof for Boruto despite them sharing the same nature I guess. He did not inherit Fire Release. Like all shinobi, he had to learn it or he would not be accepted as an adult in the clan, given their rite-of-passage technique.