I have a small problem. So, as most likely everyone accepts, dragons can change their sex depending on situation, just like many real animals. But I read somewhere in AFFC (or DwD, not 100% sure which of those two books) theory how dragons don´t need another, but even if there is one living dragon in the world, it can lay eggs and preserve the species. I couldn´t find anything about it on wiki, so I figured: Why not ask group of people who know the lore?
So, have you read it too, somewhere, or did my mind just connect ASoIaF with something I read in some other book? (It would also explain how could last Targaryen dragon lay eggs, when there was no male to make love with her)