Now this will cause a few arguments, and I'm willing to accept that most people will reject my theory, but this is a thought that came to me recently. Also note that so far in Australia we have only seen the first 15 episodes of the first series, so by now my theory may be completely out of the question. If it is, please don't spoil it by saying what is to come.
Anyway, my theory - Ted will marry Robin.
Now, I know, in episode number one he says to the kids that it was their Aunt Robin, but my question, how do we know Ted is the father of the two kids?? Is Ted actually Uncle Ted?? The title of the show is How I Met Your Mother. It doesn't mention that he is the father. He could simlpy be telling them the story of how he came to meet their mother, and possibly set them up with the kids' father. As far as I can recall, the kids have never called him Dad, nor has "Future Ted" addressed the children as his own, only as "kids", which is a term that is used by more than just the parents.
Now, I know there is a 99.9% chance I'm wrong, and rightly so, but this show's writing has always surprised me. Normally I can pick twists and turns in shows, but I can't for this one. So in response to that, if this show tells me a "fact" I start doubting it, because most of the time the show takes an unexpected twist and turns the whole story upside down. And the "fact" that Robin is only an auntie to the kids is probab;y the biggest "fact" in the show.
I'm interested to hear what other people have to say, and I understand that most of you will be against this theory. If you do have proof that it is wrong I'd prefer it if it were only in the first 15 or so episodes. If currently Ted and/or Robin have gotten together with someone else, please don't tell me, just say that my theory is wrong. Please don't provide details.