Board Thread:General Discussion/@comment-31105947-20170318035218/@comment-14909251-20170326043144

SomeoneYouUsedToKnow wrote: Some pretty-specific Semblances can be passed along. But that is not the case with Adam and Yang, whose Semblances are (very) similar, yet different, instead of being the very same Semblance like with Winter and Weiss.

Semblances reflect a part or 2 of the user's personality. And since people can only be so different from each other, similar or even nigh-identical Semblances are bound to appear. So you could take this similarity as RT saying that despite being so radically different, there's one aspect where they aren't so different.

As for Raven and Adam being so similar....honestly, I'm going to rage if it's just a coincidence. As I recall, when the idea of Semblance being passed on through family was first brought up, it was suggested that relatives are more likely to have a similar Semblance compared to total strangers even if it is not identical. We have not really seen any other characters who are so similar to each other in terms of Semblance except the Schnees how expressly have the same Semblance. Raven and Adam being connected while Adam and Yang have such a similar Semblance would make the idea of some connection between Yang and Adam seem more likely.