Alistair mentions that he knows of absolutely zero Warden couples that produced children after becoming Wardens.
I can think of a few issues with that right off the top of my head, the biggest being that Alistair was not exactly a 100% know everything about the Wardens source of information. Young recruit with not much time in service, never been to HQ in the Anderfels, hadn't scoured any records kept at said HQ for mention of pregnancies between wardens, etc etc etc.
That's a cute way of thinking. Flawed, but very cute.
My gaming experience. I don't read the books, so their content is irrelevant to me unless it is brought up in game. What a dev says, unless it is incorporated into a game, doesn't make it part of my gaming experience... because it isn't in the game. If they wanted a particular view to be "canon" then they would have included it in the game itself.