The septim bloodline isn't the only line of dragonborne to have existed. So I think whether or not the PC will be related to them is a matter of player choice than anything.IamLEAM1983 said:This. It's more than possible for the Septim bloodline to have skipped a few generations or for some Septim descendants to have bred or wed outside of Imperial bloodlines, so this could explain why Skyrim's Dragonborn could prospectively of any race or background. What helps is that the Empire has been losing its sense of direction since the end of the Third Era. Based on what's available online, you get the sense that the Imperial Legion is a corrupted shadow of its former self. I wouldn't be surprised if Ocato was still in power and basically gave the finger to the entire Elder Council, soon after the end of the Oblivion Crisis.
Considering this, your character could feasibly have some distant relationship with the Septim bloodline and have inherited a speck or two of Akatosh's power, regardless of his race or gender.
I highly doubt that Bethesda will have an official stance on it, as they have stated that the players history will be up to the player to decide.
Another point I would like to bring up. The game is set 200 years after Oblivion, it's unlikely that Ocato would still be alive, my thinking was that Bethesda did this deliberately so that cameos from the old games were impossible.