User blog comment:Project Predacon/Volume 2: Post Credits Scene Analysis/@comment-4010415-20141031003952

Dude. If Raven is Yang's mother, then it's most likely exactly as I predicted - she is Qrow's sister. Taiyang may not have married either of the women he had children with. He may not have had time to.

I mean, Raven left right after Yang was born. They may not have married quite yet, and he was expecting to settle down with her when he discovered she was pregnant, but she ended up with... other plans.

And hell, he may have been afraid to marry Summer.

As for Raven looking too much like Yang's mother,

a) It was a dream, considering it kinda looked and felt like a dream with the blurry effects going on there.

b) Something about whatever is she's doing with those portals has affected how she ages.

Hell, there are those of us who suspect Ozpin is much, much, much older than he looks, aren't there?