I am a Youtuber making a role-play series based on the Doctor Who modification in Fallout: New Vegas. https://www.youtube.com/playlist?list=PLEi6l2EjLagtqpXOWBA0UkFb8O6kqfxWd In the series I will play as the Doctor's grandson (hence the name of the series).

I have several questions:

  1. Is River Song the biological grandmother of Susan Foreman? If not, then who is?
  2. Is Susan's mother Jenny?, If not then who is?
  • The answer to both can't be "yes". Jenny is #10's cloned "daughter", so has no mother. (Unless you're speculating that River's son hooks up with Jenny, making the Doctor Susan's grandfather on both sides...) – Adeptus Aug 7 '19 at 6:52

We don't know

Very little of the Doctor's life (before the show began) has been explored on the show, and we know nothing about his family except that they existed. It's certainly possible that Susan is related to either River or Jenny, but it's never been explicitly confirmed nor explicitly denied by anything we've seen1.

If you widen your scope to the Doctor Who expanded universe, then we still don't know but it does become more unlikely; at least two works propose mutually incompatible theories for Susan's origin, both casting doubt on your theories:

  • The short story "Birth of a Renegade" raises the possibility that Susan isn't actually biologically related to the Doctor at all, instead casting her as a colleague who stowed away on the TARDIS stolen by the Doctor
  • The novel Lungbarrow proposes that Susan is the biological granddaughter of "The Other", a figure from Gallifrey's mythic past and contemporary of Rassilon and Omega. The Doctor is supposed, in this story, to be a kind of genetic reincarnation of the Other, making him Susan's grandfather only technically

All that being said, feel free to invent a new backstory for Susan for your roleplaying; it won't be any less canon than anything else we know about her, and Doctor Who has a proud tradition of retconning in any case.

1 Personally I find both to be unlikely, because it seems odd for the Doctor to not recognize the mother of his children or grandchild (and he clearly doesn't recognize either River or Jenny in their respective debut episodes). Time travel being what it is, of course, this isn't a terribly strong argument against either theory, which is why it gets a footnote


Very little is known about Susan.

To the best of my knowledge, you've already quoted everything we might know. The Doctor claimed she was his granddaughter, and Susan seems to have come with him when he ran from Gallifrey. It's entirely possible he's lying, but what little context we get implies he's not. Nothing else is known; Susan was simply dropped as a character very very early in the show's run, and no showwriter has had interest in picking her up again.

To at least eliminate or reduce speculation, River Song to our knowledge has never set foot on Gallifrey, and given her story appears to be done, never will. Susan seems to have come from Gallifrey, so her family would have been expected to be someone from that planet as well. That probably rules out most characters we've seen. It is still possible, given the wacky time hijinxs seen so far, but the Time Lords would have had to be a lot looser about time loops and paradox than we've been led to believe, so highly unlikely.



The earliest incarnation of the Doctor that knows River, is #10 (David Tennant). In Silence in the Library, The Doctor doesn't recognise River, because he's never met her (from his perspective). River, on the other hand, has known him for quite some time (but in the Doctor's future). So, if a previous incarnation ever met River, he didn't know about it. And, it would have to be before River went to the Library (from her perspective).

All we know about Jenny is that she is the cloned "daughter" of the 10th Doctor. He left her for dead, but she was revived by the terraforming device, and flew off to parts unknown. At that time, she had no way to time travel, so is unlikely to ever meet the 1st Doctor. And if she did, and he believed that she was his daughter, he'd know that it was going to happen, so wouldn't be surprised when it did.

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    This is a potentially untrue statement, as we've now seen a series of audio adventures with River meeting several past Doctors. The books, audio plays are of questionable canonicity, but they open a potential door. – VBartilucci Jan 12 '17 at 21:36

There is at least one source that states that Susan showed up from out of nowhere and TOLD the Doctor she was his granddaughter. It's entirely possible that she was from the future. Meaning she could have been born to any of the Doctor's incarnations.

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    Which source? Could you please edit it in? – Jenayah Aug 1 '19 at 7:41
  • @Jenayah its in the first episode of doctor who ever 1963 an unearthly child Susan explains shes the doctors granddaughter in the very first episode scifi.stackexchange.com/questions/144449/… – Mr Palmer I need both hands Aug 1 '19 at 8:10
  • I meant the answer as a comment – Mr Palmer I need both hands Aug 1 '19 at 8:10
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    This was meant to be a reply to the comment on this answer, please do not use other answers to comment. Instead you should wait until you have enough rep to comment everywhere. If you are the poster of the other answer you need to log back in to that account and you can comment back on that answer or even edit it. You might need to try and merge your accounts first though. – TheLethalCarrot Aug 1 '19 at 8:30
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    @MrPalmerIneedbothhands Susan calls the Doctor "Grandfather" in An Unearthly Child (and throughout her time on the show). But she didn't appear "from out of nowhere and TOLD the Doctor she was his granddaughter", so Deanna must be thinking of some other source. – Blackwood Aug 1 '19 at 15:48

River Song would be Susan's Step Grandmother and Jenny would be her Aunt, if Susan is the Doctor's Granddaughter. Since River married the Doctor, she becomes step Grandmother to Susan. The thing about Jenny is as a clone she is both a sister and a daughter of the Doctor; so how ever you see her she'd be Susan aunt. Susan's Grandmother is Patience the Doctor's first wife and it isn't known if her mother is a child of the Doctor.

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    Do you have any sources as to your information. It would help add credibility to your answer. – Edlothiad Oct 5 '20 at 6:52

I believe Susan’s mother is called Tilly, in "Invasion of the Androids" the Doctor is having a dream and he is talking to a child he calls Tilly. I believe that’s his daughter.

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    Welcome to SFF, could you edit this to explain why you believe that is his daughter? What makes you think that? – TheLethalCarrot Jan 21 at 21:51
  • I can't find any reference to "Invasion of the Androids". Do you mean "The Android Invasion"? – Valorum Jan 21 at 21:52

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