Board Thread:Theories and Speculation/@comment-5012682-20150620162706/@comment-5936871-20150620172242

@Seel and Omo I'm not saying that they inherit every single one of their natures, what I'm trying to say is that their children inherit at least one or two of their parents' dominant natures. Genetically, the Sarutobi have an affinity for Fire, but Hiruzen mastering all natures is his own trait, not from genetic lineage, which is why Asuma and Konohamaru have it too, but not all five natures.

I'm just saying that it isn't far-fetched to state that Boruto has lightning because of his mother, especially since we don't know if lightning is Hinata's affinity or not, it could fire or lightning, but it wasn't stated.