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the claim

XYY syndrome is caused by nondisjunction during paternal meiosis II

the verdict
REFUTED
the evidence says no
Recorded sources
1 source for · 1 against

Counts group repeated records of the same source within each side. They do not measure evidence strength or source independence.

Is it true that XYY syndrome is caused by nondisjunction during paternal meiosis II?

No. While multiple medical references state that XYY syndrome is caused by nondisjunction during paternal meiosis II, other sources attribute it to paternal meiosis I or postzygotic errors, making the specific meiotic stage contested in literature.

Verdict: REFUTED · 1 source for, 1 against · Last checked

The analysis

Judged against the evidence record for claims of this kind.

Evidence for · 1
Churchill Livingstone: Principles and practice of medical genetics
1983
States the likely explanation of 47,XYY is non-disjunction at paternal meiosis II.
Get citation
Churchill Livingstone: Principles and practice of medical genetics. (1983). Churchill Livingstone. https://archive.org/details/principlespracti0001unse

2 recorded entries grouped as this source

Additional records of the same source are shown below. They are not counted as additional sources.

Churchill Livingstone: Principles and practice of medical genetics
1990
States the likely explanation of 47,XYY is non-disjunction at paternal meiosis II.
Get citation
Churchill Livingstone: Principles and practice of medical genetics. (1990). Churchill Livingstone. https://archive.org/details/principlespracti0000unse

Evidence against · 1
Double Aneuploidy of Down Syndrome (Trisomy 21) and Jacobs Syndrome (Trisomy XYY) with Complete Tracheal Rings Deformity: Case Report and Literature Review
2023
Claims trisomy XYY results from nondisjunction during paternal spermatocyte meiosis-I, contradicting meiosis II.
Get citation
Adeleke, O., Elmufti, H., Zhang, J., Jagadesan, B., & Harsono, M. (2023). Double Aneuploidy of Down Syndrome (Trisomy 21) and Jacobs Syndrome (Trisomy XYY) with Complete Tracheal Rings Deformity: Case Report and Literature Review. peer-reviewed literature. https://doi.org/10.1055/s-0043-1774728

What does the evidence say?

Judged against the evidence record for claims of this kind.

Receipt History
first checked06 Aug 2026
judged → REFUTED · 4406 Aug 2026
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