Official Forum Thread (2011)
So this has since been expanded on a little bit through the quests that Skae mentioned. The Hilda quest is likely what the "Future/Quests events" referred to.
I do not quite remember where, if it's an official source like the Lore Panels or somewhere else, but I believe it has been phrased that the more different the races are, the more difficult it would be for a couple of said combination to have a child. This is also seen by the fact that half-breeds within each race's clans are a fairly common sight among NPC's, especially with seeker/keeper miqo'te's (so you may have a child NPC that presents with sharp teeth - a keeper trait, and slitted eyes, a seeker trait). Through this logic I can only guestimate that typical racial features would be distributed at random with any half-breed child, so that would be up to you.
So the answer is yes, you can, but it would be very rare and I would encourage you to consider this when as you progress through roleplay; from having problems with it, all the way through to the potential stigma there may be from other inhabitants of hydaelyn that a mixed couple has managed to produce such a child. Personally I don't think a roegadyn and a viera would have as many problems as e.g a roegadyn and a miqo'te would, but both combinations would be rare still regardless. I also think when it comes to things like this, it's all about how you integrate it into your RP and less so important that the lore says it's improbable.