The grandfather paradox - X goes back in time and prevents his own birth - is only a paradox if you assume a non-branching timeline.
Thanks, that's not what I am meaning.
Given the premise, it would be possible for someone, who was a time-traveller, to cause their own events.
In this case, where someone can be a woman and then a man (I was more willing to believe in time-travel that that part, tbh), they can cause events as a woman and a man.
The issue of what 'causes' something could be seen to be a paradox only if you are determined that things have to have causes which happen before the events and, for instance, you can't have closed loops and there must be an 'outside' influence.
With the introduction of time-travel, that isn't a hurdle anymore.
The temporal flipping of cause and event isn't the relevant paradox. That could happen if tomorrow I invent a time machine, buy a newspaper, look at the lottery numbers for last week's ticket, go back in time and buy the ticket, come back to the present, and cash the ticket. No pardox, even though the cause (learning the numbers) happens after the outcome (buying the ticket).
To see the paradox, imagine the following story - a time travelling self-aware robot goes back from the year 2011 to July 10th, 2009, where it builds itself, then self-destructs. In the year 2012, an asteroid crashes into the Earth, killing all humans. The time travelling robot never taught anyone the time-travel technology, and humanity didn't survive long enough to invent it.
The question is - where did the time-travelling technology come from? The robot knew it, so it built it into itself. But no-one else knew it, no-one invented it. It only existed as part of a closed loop. For that matter, the same is true of self-aware AI technology in this story. Humanity couldn't have invented it.
Now, note that this story could have happened at any time and any place. A time-travelling robot came into existence on the moon in the year 1132, and existed there until 1212, at which point it went back in time. It didn't even have to build itself, it just shows up and waits 80 years to travel back. It interacts with nothing, and affects nothing. It doesn't even move, and it hovers above the surface of the moon using anti-gravity technology, so it doesn't even displace moon dust. Where did it come from? Why was there a robot in the middle ages?
This is a paradox; it's not that the order of cause and effect is reversed that is the problem. The problem is that the cause and the effect are one and the same. Which is a basic problem in what we think of causality.
This made me realize, by the way, that the story is entirely biologically plausible. Humans can be self-impregnating hermaphrodites, but then, the hero of the story isn't really human. He's a being that was created
ex-nihilo, and there's no reason to think that he would share anything of human genetics. It's actually the fact that he looks and acts human that's totally implausible. Of all the things that could just randomly appear out of nothing in the universe, I would think it would be quite unlikely that a human would be one of them. And, if a human was randomly created in this vast universe, it would be an staggeringly massive coincidence if he/she happened to appear on Earth, where all the other humans are.
