.... obtain the soul of a dragon. I believe that he/she was born with it but does that mean that it was pre-determined to a specific somebody, like divine interference. or was it all just kind of random?

I thought Dragonborn meant blood of a dragon, not soul. Parthunaax refers to you as having "Dova Sos," meaning dragon blood. And, per the greybeards, it is a "gift from the gods." Akatosh specifically.

Actually I think the dragonborn has the soul of a dragon, and having the blood is different. I think Martin Septim was the last mortal to have the blood? Correct me if im wrong.

I could certainly be wrong, but I did just play that part of the main quest last night, and Parthunaax specifically says "the dragon blood runs strong in you." Paraphrasing. It could be both though. In a mythological sense, having a dragon soul, or dragon blood are fundamentally the same things.

Yeah think ur rite,decended from talos to the sceptims,I'm not hugely confident in my answer but I think it's right.

I looked it up http://www.uesp.net/wiki/Skyrim:Dovahkiin and I think we are both right? He is born with a soul but the dragons call it dragonblood?

I always throught it meant a bloodline of dragonic humans? Kinda like how Charlie Sheen has Tiger's Blood.

Indeed, I think the words blood and soul become interchangeable here. Still, it is confirmed that it is a gift from Akatosh.

Does that mean Akatosh chose that person to bestow it upon him/her or was it random?

Akatosh either chose you, or you simply came from a Dragonborn bloodline.

Extrapolating from what we already know about Alduin and the prophecy of his return, I believe you were specifically chosen by Akatosh to defeat Alduin. It is no coincidence that the Dovahkiin was caught crossing the border into Skyrim itself, and whose execution was stayed because of Alduin's interference. Alduin and Dovahkiin are fated to battle I believe, similar to the Neravarine and Dagoth Ur. At least, that is my take on it.

Born of dragon, you plopped out of a dragon [censored].

I thought about this, but there is no evidence to support that the Dovadude has a dragon bloodline. Wouldn't the blades have found one of his ancestors to have the dragon blood before 200 years after Martin's death? On the other hand, if there were no dragons around in 200 years to fight and absorb their souls, how would anyone even know if they had dragon blood or not?

Exactly. It's honestly unclear just how widespread the Dragonborn bloodline really is. You might be the last of your kind, or over 10% of the population might be Dragonborn, kinda like Atilla the Hun (I think?).

The Septim family were the only ones to have a heritage of dragon blood, that why they could light the fires. After Martin died that family line ended, I think the Dragonborn didnt come from a family but was simply blessed by Akatosh.

Doesn't the game explicitly tell you being born with the soul of a dragon is a gift from akatosh?

Yes we know that but why was he chosen or why?

So somebody would stop Alduin. Perhaps Akatosh was sick of Alduin making him look bad... and perhaps something else that we will understand after Dragonborn (the DLC) is released.

Again, all evidence in game supports my theory that you are specifically chosen, at birth, and by Akatosh, to both herald the coming of Alduin, and defeat him. No coincidences when gods are involved.

Ah yeah akatosh,I remembered it being in oblivion when Tiber becomes the embodiment of akatosh and turns into a dragon to fight mehrunes dagon,not talos soz for the poor info.

It seems like Divine intervention but similarly why would Akatosh have someone kill his own son. I figure it was either a gift of Akatosh's or Kynoreth intervened once more. They had once before so why not now when the world is at it's most threatened.

I know there is a big difference between the gift of Shouts and a Dragon soul but I still think Kynoreth might've played a part somehow despite the lack of evidence...

The artifact known as the Amulet of Kings was created by Akatosh. As lord of the Aedra, Akatosh took pity on the plight of Men, who were slaves of the Ayleids,[13] and, drawing precious blood from his own heart, blessed St Alessia with the blood of Dragons, and made a Covenant that so long as Alessia's generations were true to the dragon blood, Akatosh would endeavor to seal tight the Oblivion Gate, and to deny the armies of daedra and undead to their enemies, the Daedra-loving Ayleids.[14] He then gave her the Amulet of Kings, and the Eternal Dragonfires, which, when lighted, would restrict the Daedra to the realms of Oblivion. The Amulet contains a gem of Alessia herself, and eight other gems, one for each of the Eight Divines [14] The Remanada mentions the amulet, and how it was a symbol of the Reman Dynasty, how it was lost during the Interregnum, before being found by Tiber Septim. [15]
****went to wiki,also Tiber septim became talos.

I just always assumed it was by the will of Akatosh. Seems the most logical and simplest answer.

it isnt hereditary, being the kid of a dovakiin does not make you dovakiin and the dragonblood does not make you dovakiin

Eh, I always figured the Septims were Dragonborns, they just never thought to ever go to High Hrothgar for training. Nor were there any dragons about.
In fact, prior to Skyrim, the only appearance of a Dragon was in the spinnoff game Redguard.
Or maybe there was one in Daggerfall as an NPC...I forget.