Board Thread:Speculation House/@comment-24177652-20150127071507/@comment-25555436-20150206202040

81.82.134.30 wrote: I Thought Raven looked way too young to be Yangs mother but she is definatly related to Qrow, even the names make that much obvious Not to a 100% though. In Real Life, many people have the exact same last name, yet are completely unrelated. There are thousands of Kennedys, Gonzalezes, and others. Yet only about some dozens are directly or almost-directly related.

In other words, having the same last name is a strong evidence that she could be directly related by blood or not to Qrow, when combined with the similar naming. However, it's not a 100% decisive evidence. I say, around 87%.