Board Thread:Wiki Discussions and Support/@comment-995176-20141123043523/@comment-25708482-20141126234720

Red hair is a recessive gene meaning 'both'parents had to carry the gene for their children to have the potential to have red hair. Because of this if Minato did not have this gene at all then its impossible for Naruto to have had red hair. Since Naruto has the recessive gene but Hinata obviously did not give the heritage of the hyuuga clan then their children wouldn't have had red hair because of this. Even if somehow they both possess the gene, keep in mind its recessive and not a dominant trait so it would be rare to pass on anyways. Remember, both parents much possess the gene(not red hair) for it to be possible, though still unlikely.