Tender Bender posted:

One theory that I think isn't too wild and is consistent with the source is the idea that Targaryens and the other dragon-riders in old Valyria were the product of some kind of magical genetic engineering to give humans Dragon attributes, hence why they have a supernatural bond with them (or maybe dragons themselves are the end result of that experimentation). Some of the weird poo poo like Dany's stillborn son with scales and claws ties into this, and especially what we hear about people who go to Old Valyria and make it back.