Muggleborn wizards are wizards born of Muggles (obviously). They tend to be born due to some wizard ancestor far back in their lineage. As their inheritance of magical powers generations later is a statistical anomaly, do they have a lower chance of giving birth to magical children (when paired with a pure wizard) than a pure wizard couple?


  • tend to be born due to some wizard ancestor care to back your claim up with any kind of data whatsoever?
    – n611x007
    Jan 25, 2017 at 10:44
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    @n611x007 - I back up that claim in my answer.
    – ibid
    Jan 25, 2017 at 10:49
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    @n611x007 I like how you came into my question with a bone to pick. You're funny.
    – user40790
    Jan 25, 2017 at 16:40
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    glad to hear my comments work for you. it's worth giving them out then. too bad they fell pray to lot of censoring lately, hope mods realize it gives the look of a one-sided conversation if funny comments get deleted.
    – n611x007
    Jan 25, 2017 at 16:55
  • duplicate-ish? scifi.stackexchange.com/questions/119770/… (I say -ish because OP is same on both so I've refrained from voting to close :)
    – NKCampbell
    Jan 25, 2017 at 18:24

2 Answers 2



The second WOMBAT test which Rowling wrote had a section about Muggle Studies. One of the questions listed five "widely held beliefs", and stated that only one of them was true.

Question 16 out of 18
The following beliefs are all widely held in the wizarding world, but only ONE is actually TRUE. (According to the latest research from the Institute of Muggle Studies) Which is it?

☐ Muggle-born witches/wizards are more likely to produce Squib children than those who have one or more wizarding parents.
☐ Muggle-born witches/wizards usually have a witch or wizard ancestor somewhere in their family tree, though s/he may be generations back.
☐ Muggle-born witches/wizards are generally less prone to certain magical illnesses than those who have one or more wizarding parent.
☐ Muggle-born witches/wizards are generally slower to show signs of magic in childhood than those who have one or more wizarding parent.
☐ Muggle-born witches/wizards have great natural rhythm.
(W.O.M.B.A.T. Grade Two - Part Four)

It was determined by a fan named Roonwit (based on extensive testing to see which answer choices affected one's grade) that the second choice was correct. Additionally, this can be seen from the Bloomsbury.com webchat that Rowling gave the following year.

Katie Mosher: How exactly do muggleborns receive magical ability
J.K. Rowling: Muggle-borns will have a witch or wizard somewhere on their family tree, in some cases many, many generations back. The gene re-surfaces in some unexpected places.

Based on how the question is worded, all the other choices must then be false. Therefore, we can safely conclude that Muggle-born witches/wizards are NOT more likely to produce Squib children than those who have one or more wizarding parents.

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    This is when we find out that the second one is bunk and all muggleborns have great natural rhythm.
    – user40790
    Jan 24, 2017 at 19:38
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    Sounds like JKR's knowledge of genetics is rivaled only by her mathematical prowess. Jan 24, 2017 at 22:32
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    @CodesInChaos - scifi.stackexchange.com/a/140403/55866
    – ibid
    Jan 24, 2017 at 22:35
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    What is the source of this WOMBAT test? Pottermore? And do we know that J.K. Rowling wrote it? Jan 25, 2017 at 5:30
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    @CodesInChaos actually, no. This makes perfect sense in real world genetics. If the muggle-born is a witch/wizard and assuming that is a genetic trait, then they are carrying the relevant alleles. Just the same as any pure blood. So no, there's no reason to assume they have any higher chances of giving birth to a squib.
    – terdon
    Jan 25, 2017 at 13:11

A Squib is someone who was born into a wizarding family but hasn’t got any magic powers. Kind of the opposite of Muggle-born wizards, but Squibs are quite unusual. - Chamber of Secrets

They are already extremely rare, but they will happen even in pure blood families, so I think that precludes the idea that Muggle-born wizards are more likely than not.

Some pure-blood families, such as the Blacks, disown any Squib members and remove them from their family trees, as they removed Marius Black. - Harry Potter Wiki (referencing Black family tree).

That doesn't stop some families for blaming Muggle-born wizards for a squib being born.

Some magical families would often blame any Muggle parents for a Squib's birth, as Orford Umbridge and his witch daughter would blame his Muggle wife, Ellen Cracknell, for being the fault of the son being born a Squib. - Harry Potter Wiki

Additionally the Weasley's have a second cousin who is a squib which they never talk about.

Squib's might have a better chance of producing magic born children, as in an early draft of Goblet of Fire, the second cousin had married a muggle and had a witch daughter. Perhaps that is the source of Muggle-born wizards, they are descendants of squibs who were cast out of the Magical World and their genes eventually came back into play.

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