Spoilers for S9 follow. Proceed with caution.
Most fans are aware of a bit of personal history the Eighth Doctor let slip back in 1996:
Many of those fans would prefer to forget he ever said it. It was an American add-on, an attempt to make the Doctor more relatable to xenophobic Yanks, a nod to Spock maybe. It wasn’t the Doctor.
But then Russell T. Davies said otherwise: that we can’t ignore the Doctor’s reference to his own humanity. Which he then proceeded to do for five years. He said it, and he dropped it, leaving the question unaddressed.
(Here’s the spoilery bit. You’ve been warned.)
Now, in ‘Hell Bent,’ Lady Me picks it up again. Is the Doctor human? Is he the Hybrid? Is that why he loves the Earth so much he can’t stay away? The Doctor declines to state, but the pot is stirred.
For purposes of the story, of course, the Doctor isn’t “the” hybrid. In fact there isn’t really “a” hybrid – it’s the combination of the Doctor and Clara that threatens Time Lord existence somehow. The details are not important – and once again, the question goes unanswered.
But one other thing struck us as odd about this episode: the speed with which the General recovered from regeneration. The Doctor spends hours or even days, every time, confused, amniesiac, and otherwise unhinged. The General stands up, brushes herself off, and gets on with her day.
(Spoilers over. You may proceed.)
The theory my husband proposes is that the Doctor’s human DNA interferes with the regeneration process. He’s enough Time Lord that he can do it, but enough human that he can’t do it well. We haven’t personally seen enough other Time Lord regenerations to make a suitable comparison: just the one above, and the Master in ‘Utopia,’ which doesn’t really count since any regeneration sickness would be indistinguishable from his usual level of lunacy. (Or maybe John Simm’s entire run was recovering from regeneration. That would explain a lot.) But in ‘Destiny of the Daleks,’ I believe, Romana tries on faces and forms like hats, with no apparent ill effect. She has perfect control. The Doctor suffers a “lottery.” (A heavily weighted white male lottery – perhaps an effect of his human inheritance?) No other Time Lord has had the Doctor’s difficulties.
On the other hand, River Song is entirely human, and regenerates with no trouble in ‘Let’s Kill Hitler.’ So maybe that’s not it after all.
Here’s the full writeup, for interested parties.
But I have a better head canon. The Doctor isn’t genetically half human. Instead, perhaps he spent an impressionable portion of his childhood in the care of a human woman – the companion of an adventurous ancestor, perhaps, his predecessor in interference – and she made such an impact that he considered himself part human for her sake. Perhaps his own mother died young, and he put his hearts in this woman’s hands. It would explain his affection for her lineal sisters. It would explain his passion for her home world. It would explain his unwillingness to behave like a proper Time Lord. He knew that something more existed, that other kinds of lives were lived on other kinds of worlds, and he wanted nothing more than to see them for himself.
It’s a theory, anyway.
Speaking of head canons – and this bit’s really spoilery:
‘Hell Bent’ ends with Clara and Lady Me flying off to see the universe in a TARDIS with a wonky chameleon circuit. ‘The Name of the Doctor’ proposed that it was Clara who pointed the Doctor in the direction of his eternal friend in the first place. It was suggested on this week’s Fan Show that the two machines are one and the same: Clara returned her TARDIS to Gallifrey, and offered it to the fleeing Doctor.
My first reaction to this idea was that the timelines don’t match up, but this is Doctor Who and therefore that sort of thing is only to be expected. My actual objection is the same as I had when ‘The Name of the Doctor’ aired:
Nobody retcons Neil Gaiman.