@Ibri Yeah, that's true, however we must also remember that the differences between siblings only start to show as they get older, so while they are still in their adolescence they should still be fairly similar in their appearance. Also, my comments over them being asian is not born out of prejudice or ill will: it's a fact that the sexual dimorphism that let's us differentiate between men and women is, in average, less accentuated in people with asian traits, with some of them being clearly of a distinctive sex and others being
confusing as hell. A last point for my hypothesis would be the fact that, for some reason, nowadays it's become more popular for males to look less masculine and, in some cases, slightly feminine, with asian countries being the extreme of this recent fashion.
However, what you said about them not being identical twins is certainly true, which takes away a great deal of my argument of them having the same face, not to mention the fact that the artist draws everybody the same, so pretty much everybody looks alike. There's also the reality that the facts that I mentioned in my previous paragraph are averages (and, well, let's be honest, there were some special cases there too), which don't always apply to individual people.
So yeah, all my talking aside, you were right about them not being identical and I was wrong about them having the same face, so I guess I was just talking out of my ass on my previous comments (and on this one too).