User blog comment:DiegoAnime3000/Why they have different last names? Answer found here./@comment-3146930-20140725032750/@comment-3257939-20140725052552

I'm against that idea because of the great relationship between Yang and Ruby, also, how good these girls are. I never mentioned it because it's just my own opinion but I think they were obviously raised well by two caring parents so I doubt that there was any kind of problem like Ruby having to visit her father instead of living with them. She mentioned him twice and her mother only once after all.