It's All Coming Up Doctor - Journey's End Meta on Clones and Hybrids
This one's for you, wendymr ;)
Ah, Journey's End. It's been a ripe ground for fanfic. There's your fixit fanfic, where Rose ends up with the full Time Lord version of the Doctor or Donna gets her memories back and continues travelling through time and space with her best mate. There's your post-episode, what happens next, fic where we get to see the struggles our heroes go through as they live their lives. They're brilliant most of them and I do enjoy reading them, but I've noticed a trend as of late. And that trend regards just what the half Time Lord/Half Human Doctor actually is. I've seen the word "clone" thrown about amongst some other, not very complimentary words.
So, let's start with that. What is a clone? A clone is someone who is genetically identical to the original person. These are generally formed by duplicating cells in a lab setting. Is the Doctor Version 2.0 (I've got to call him something here, and I don't fancy blue!Ten or human!Ten, because that's not entirely true) a clone? No. Why, you ask? Well, he came into being from three things:
1) The Doctor's hand - which is a piece of him, sort of like a lizard/worm as Donna said
2) Donna - I'll get back to her
3) Regeneration energy - which is another part of the Doctor, something that is a natural process of any Time Lord when they're dying
Mix those three things together and you get the Doctor Version 2.0. Is he genetically identical to the Doctor? No. There's that whole bit about having only one heart and a human lifespan. So he's not a clone.
Is he human? Actually, I don't think he is. He's got a Time Lord's brain - otherwise he'd go 'splodey like Donna was going to, and that'd just be too cruel for the Doctor to put Rose through. He's got to have some biological quirks that all Time Lords have, just not to the strength or intensity of a full Time Lord. Now, I'm totally ignoring the Eighth Doctor movie here (they said he's half-human on his mum's side). So, what we really have is a Time Lord/Human hybrid. And biology says no timebabies are likely to be possible in this case, because all hybrids are almost always sterile, if you go for that sort of thing
Now, the biggest question on everyone's minds (and fics) is whether he's actually the Doctor. Now take a look at the three components that make up who the Doctor Version 2.0 is:
1) Doctor's Hand
2) Donna
3) Regeneration energy
Now that regeneration energy is important. That energy takes the Doctor's body, his cells, his entire being and re-writes it while maintaining the same memories, emotions, etc. There will be new personality quirks and a different appearance, yes. But the contents of those memories and emotions remain the same. Throw that energy into the hand. The hand is a piece of the Doctor. The regeneration energy contains the Doctor's memories and emotions (how else can he maintain that if every cell in his body is being re-written?). Throw in that bit of Donna's humanity and what do you get?
The Doctor Version 2.0. He's got the memories, emotions and thoughts of the Doctor. And what makes you who you are? Your memories. Your experiences.
So is the Doctor Version 2.0 the Doctor? Yes.
Think of it this way. When the Ninth Doctor regenerated into the Tenth, did he somehow become someone other than the Doctor? Is "the Doctor" just a name? No. Who and what the Doctor is is the sum of his memories. Those memories are in that regeneration energy.
Ergo, Nine = Ten = the Doctor. Following that same logic, Ten = Ten Version 2.0 = the Doctor.
Did Rose get the bum end of the deal, getting saddled with a hybrid Doctor Version 2.0 and no TARDIS? No. Because the Doctor gave her the one thing he never could.
Forever.
And that's the simplest equation of them all :)