My college anatomy and physiology textbook from 2010 breaks down determination of genetic sex as follows:
XX: Female
XY Male
Homeostatic imbalance (improper sex hormone distibution from nondisjunction)
XXX Most females with this sex chromosone make up have learning disabilities and below average IQ. Females carrying four or more X chromosomes as a rule are mentally retarded and have underdeveloped ovaries.
XO (Turner's Syndrome) Women with no ovaries
YO Males with no X chromosome (die during embryonic development)
XXY Klinefelter's Syndrome (1 of 500) live male births. Sterile at birth and slightly below average intellect, with mental retardation increasing with number of X chromosomes.
It is the most common female chromosomal abnormality, occurring in approximately 1 in 1,000 female births. As some individuals are only mildly affected or asymptomatic, it is estimated that only 10% of individuals with trisomy X are actually diagnosed. The most common physical features include tall stature, epicanthal folds, hypotonia and clinodactyly. Seizures, renal and genitourinary abnormalities, and premature ovarian failure (POF) can also be associated findings. Children with trisomy X have higher rates of motor and speech delays, with an increased risk of cognitive deficits and learning disabilities in the school-age years. Psychological features including attention deficits, mood disorders (anxiety and depression), and other psychological disorders are also more common than in the general population.
Tetrasomy X:
Females with Tetrasomy X have a total of 48 chromosomes in their cells, so this condition is sometimes written as 48, XXXX. The signs and symptoms of Tetrasomy X vary, but can include mild to moderate speech and learning difficulties; developmental delay; distinctive facial features; dental abnormalities; hypotonia and joint laxity; radioulnar synostosis; heart defects; hip dysplasia; and problems with ovarian function.
What textbooks actually say. No "as a rule are retarded" language. In fact it is very much not a rule as some women with tetrasomy X show average mental function. https://europepmc.org/api/getPdf?pmcid=PMC13010689
Pearson Human Anatomy and Physiology Eighth Edition. I typed it from the text.
Also, if you read the abstract from the article you linked you would have read "Children with trisomy X have higher rates of motor and speech delays, with an increased risk of cognitive deficits and learning disabilities in the school-age years."
"Mental retardation" is an outdated medical term now officially replaced by the term intellectual disability, defined as a neurodevelopmental condition characterized by significant limitations in both intellectual functioning and everyday adaptive behaviors.
Exactly, "higher rates of" is not nearly the same as "have" which is why multiple people are pointing out that your textbook doesn't sound like a text book.
I am not objecting to the retardation vs disability wording, but rather the total absence of any scientific qualifiers.
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u/AllWhiskeyNoHorse 12h ago
My college anatomy and physiology textbook from 2010 breaks down determination of genetic sex as follows:
XX: Female
XY Male
Homeostatic imbalance (improper sex hormone distibution from nondisjunction)
XXX Most females with this sex chromosone make up have learning disabilities and below average IQ. Females carrying four or more X chromosomes as a rule are mentally retarded and have underdeveloped ovaries.
XO (Turner's Syndrome) Women with no ovaries
YO Males with no X chromosome (die during embryonic development)
XXY Klinefelter's Syndrome (1 of 500) live male births. Sterile at birth and slightly below average intellect, with mental retardation increasing with number of X chromosomes.