Despite the conventional wisdom and closed statements many make on this topic, it is not a given that Elizabeth is Victoria's mother.
The great thing about fandom is that it's possible to debate and deconstruct all the unresolved questions on DS. However, I believe that the vast majority of fans believe that Liz is Vicki's mother because 1) Joan Bennett had commented that she was told almost from the very outset that Liz was Vicki's mother and that's how she always played their relationship, and 2) DS producer Robert Costello has commented that, after they hired Alexandra Moltke and saw her resemblance to Bennett, they decided to deviate from Art Wallace's bible and make Liz Vicki's mother. And they didn't make these comments while DS was originally on the air, but years, even decades after it had been cancelled. One can't help but understand how comments from two people so closely associated with DS might hold more weight with fans than any theories we fans might come up with, no matter how well researched they may or may not be.
But as I said, debate is and always will be a really wonderful thing. And we should never not engage in it simply because it seems as if a lingering question was resolved in a way other than during the course of the show (like Bennett and Costello's comments). If there wasn't ever an explicit and definitive answer to a question in the actual episodes, then it is and always will be up for debate...
I'm hoping that the original thread (I think it was called "Victoria Winters Parentage" or something like that could be accessed from the forum archives??
Unfortunately that isn't possible. For some sad reason that topic is the only topic that ever became corrupt while we were with our old host. We never realized that until we converted the system from YaBB SP to SE, but it wouldn't have mattered because we soon discovered that even all of our backups of the topic were also corrupt.
Could someone - or someTHING - have been trying to tell us something?