Think about it. An ancient, “magical” city, populated by mystical people with pale skin, silver hair, purple eyes, and dragon mind-meld powers. Could the “magic” really be advanced alien technology, and dragons aliens creatures, brought from another world? Could the Valyrians be another species?
If Dany gets preggers, then I think there’s a strong chance its true. To me, it would explain why she wasn’t able to conceive with Drogo but Jon was able to get kick one past the goalie on the first try. If Valyrian’s are aliens, and knowing that the Targaryens are descended from Valyria, it would make sense that the likelihood of conception would go up when two Valyrians knock the boots. This would also explain why the Targaryens are known to inter-marry. What comes across as incest to “modern” Westeros is is actually a tradition born from a different race trying to preserve its purity. You could assume that the Valyrians knew that interbreeding with the locals was risky, and diluted their “magical” powers.
What if the reason you can’t make new Valyrian steel is because the original came from the ships that brought the Valyrians to the planet in the first place? We know that non-Valyrian smiths can reforge Valyrian steel, so its not the smithing process thats unique. What must be unique is the source of the material itself, which is actually another world altogether.
Even if there is some truth to this, I doubt it will ever be fully explained in the books, much less the show. While I think it would be a neat twist, it would probably throw the majority of the fan-base for a loop.
Planet Zack 