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-   -   Differences in Sex Development (aka "intersex") (http://www.internationalskeptics.com/forums/showthread.php?t=355523)

d4m10n 22nd November 2021 08:07 PM

Differences in Sex Development (aka "intersex")
 
https://en.wikipedia.org/wiki/Disord...ex_development

DSD's come up a lot in the threads about gender, but they aren't really about gender except in the sense that (rather rarely) parents don't know which set of gender norms to invoke when raising their children.

Since I hate to start a thread without a question, what fraction of people born with DSDs are really ambiguous between male and female? We can safely rule out girls with Turner Syndrome and boys with Klinefelter Syndrome, I'd suppose.

arthwollipot 22nd November 2021 08:18 PM

Quote:

The number of births where the baby is intersex has been reported differently depending on who reports and which definition of intersex is used. Anne Fausto-Sterling and her co-authors suggest that the prevalence of ″nondimorphic sexual development″ might be as high as 1.7%. Leonard Sax says that this figure includes conditions which most clinicians do not recognize as intersex, and that in those ″conditions in which chromosomal sex is inconsistent with phenotypic sex, or in which the phenotype is not classifiable as either male or female", the prevalence of intersex is about 0.018%.
https://en.wikipedia.org/wiki/Intersex

Delvo 22nd November 2021 09:49 PM

That depends on what you call "really ambiguous". It's easy to call somebody with Turner Syndrome a "girl" because that person looks female on the outside, but the lack of a vagina or uterus or developed ovaries on the inside makes such a person "really ambiguous" in my book, and the word "girl" not really accurate (at least not biologically even if it's usable enough socially). If these conditions weren't "really ambiguous", they wouldn't be "intersex" conditions.

d4m10n 23rd November 2021 06:33 AM

Quote:

Originally Posted by Delvo (Post 13662056)
That depends on what you call "really ambiguous".

I mean some sort of mismatch between chromosomal sex and phenotypic sex, resulting in phenotypes which are difficult to classify as either male or female, especially individuals who cannot produce either oocytes or spermatozoa.

Quote:

Originally Posted by Delvo (Post 13662056)
It's easy to call somebody with Turner Syndrome a "girl" because that person looks female on the outside, but the lack of a vagina or uterus or developed ovaries on the inside makes such a person "really ambiguous" in my book...

I cannot find a reference to lack of a vagina, but there are a number of other physical features mentioned in the relevant wiki, including "webbed neck, a low hairline, a small chin and jaw, a high-arched palate, and a broad chest with wide-spaced nipples."

Planigale 23rd November 2021 08:56 AM

Complete androgen insensitivity (1: 20,000 - 1:100,000 live births) causes an XY (genotype male) to be born with a female phenotype. Prior to puberty there is no obvious way to distinguish them from pre-pubertal XX females. The issues arise at puberty when they do not menstruate (no uterus or ovaries). Androgen insensitivity means telarche (sexual hair development) is delayed or absent. The vagina is usually under developed so the affected person has to dilate if they want to have penetrative vaginal sex. This is the most common form of 'intersex'.

Most affected persons have been brought up as female and identify as female, few become trans men. In many ways they are similar to trans women in that they will never menstruate or become pregnant and usually have to take some hormone supplements.

What they do not have is 'ambiguous genitalia', which is what is often meant in intersex. Either cliteromegally or micropenis. Partial (mild) androgen insensitivity causes more ambiguous genitalia with under development of male genitalia and development of breast tissue at puberty, this would be the most common cause of intersex with ambiguous genitalia.

Louden Wilde 23rd November 2021 02:38 PM

Quote:

Originally Posted by Planigale (Post 13662305)
Complete androgen insensitivity (1: 20,000 - 1:100,000 live births) causes an XY (genotype male) to be born with a female phenotype. This is the most common form of 'intersex'.

The activists who push the 'sex is a spectrum' idea or similar often include CAH (congenital adrenal hyperplasia) in this group - only potentially applicable as a DSD to females. But it's more frequent - 1 in 8,000 to 1 in 29,000. I see the causal variants a lot in my job (clinical genetics in NYC). I'm surprised that those activists don't try and include cystic fibrosis (more common still) since CF males typically lack a vas deferens.

d4m10n 24th November 2021 09:17 AM

Quote:

Originally Posted by Louden Wilde (Post 13662715)
The activists who push the 'sex is a spectrum' idea...

I'm not sure what it would take to convince me that sex is a spectrum. I've seen the Quigley scaleWP and that convinces me that genital morphology is indeed a spectrum, but I tend to think of sex as an evolutionary adaptation which facilitates reproduction of individuals. Since these individuals have to contribute different sex cells (oocytes and spermatozoa in our species) I'd say the process of sexual reproduction is rooted in a binary at the gamete level.

Louden Wilde 24th November 2021 10:09 AM

Quote:

Originally Posted by d4m10n (Post 13663259)
I'm not sure what it would take to convince me that sex is a spectrum. I've seen the Quigley scaleWP and that convinces me that genital morphology is indeed a spectrum, but I tend to think of sex as an evolutionary adaptation which facilitates reproduction of individuals. Since these individuals have to contribute different sex cells (oocytes and spermatozoa in our species) I'd say the process of sexual reproduction is rooted in a binary at the gamete level.

Yes, evidence suggests that every therian mammal that has ever reproduced has done so either by producing one of those two gamete types. Sex seems to be the preferred method of reproduction over parthenogenesis due to its conferring novel genetic combinations. In fact, mammals have evolved differential epigenetic marking of some genes in the two gametes (resulting in their silencing) that precludes parthenogenesis. Meaning you need one of each gametes type for normal development.

ETA- the pseudo-penis of spotted hyena (Crocuta crocuta) females is the classic example of what you're saying.

& it should take a new gamete type/reproductive role to convince anyone that their is another sex besides female & male.

Silly Green Monkey 25th November 2021 01:31 AM

This is confusing the binary of sex gametes (egg vs sperm) with the physiological expression of the underlying genetic makeup, and also combining it with the judgements humans as a society have made on how each sex looks and behaves---what makes a male a man or a female a woman. Phenotype is the physical outcome of the genotype an individual starts with, where the genetic interaction and womb environment and even early childhood take the original two flavors and spread them into a spectrum. Genital size and shape, limb dimensions, body shape, all start from the same source and take infinite paths from there. It's a fool's errand to try to narrow down exactly what marks an individual as belonging to one category or another, because while the source is simple (ish), it's only the beginning of development and all we see is the end.

That's also entirely leaving out the societal influences, what non-physical traits are assigned to each sex and the relative value associated with them.

d4m10n 25th November 2021 03:47 PM

Quote:

Originally Posted by Silly Green Monkey (Post 13663994)
This is confusing the binary of sex gametes (egg vs sperm) with the physiological expression of the underlying genetic makeup, and also combining it with the judgements humans as a society have made on how each sex looks and behaves---what makes a male a man or a female a woman.

Can you be more specific as to referent of the highlighted word?

Seems to me that the gamete binary accounts for > 99% of live births, that is, people who are born with oocytes or on a developmental pathway to produce sperm. The remaining fraction of a percent are the subject of this thread, and a fascinating subject in and of itself, quite apart from "judgements humans as a society have made on how each sex looks and behaves." I was surprised to learn (for example) that individuals with de la Chapelle syndromeWP may be fully masculinized due to the presence of an anomalous SRY gene, despite being genetically 46,XX.

Louden Wilde 26th November 2021 12:38 PM

Quote:

Originally Posted by d4m10n (Post 13664483)
Can you be more specific as to referent of the highlighted word?

Seems to me that the gamete binary accounts for > 99% of live births, that is, people who are born with oocytes or on a developmental pathway to produce sperm. The remaining fraction of a percent are the subject of this thread, and a fascinating subject in and of itself, quite apart from "judgements humans as a society have made on how each sex looks and behaves." I was surprised to learn (for example) that individuals with de la Chapelle syndromeWP may be fully masculinized due to the presence of an anomalous SRY gene, despite being genetically 46,XX.

But note folks with this syndrome are sterile (so it's still definitely a DSD) - likely due to incompatibilities between X chromosome inactivation in mammals and being a functional male. There are rodents (notably genus Tokudaia - "spiny rats") that lack a Y Chom and mostly SRY, but they are X/0. Note the main function of the SRY protein is to trigger expression of a related gene/protein, Sox9 that subsequently starts the male developmental cascade - these rodents have a Sox9 gene, but it does not respond to SRY protein

Emily's Cat 29th November 2021 12:45 PM

Quote:

Originally Posted by Silly Green Monkey (Post 13663994)
This is confusing the binary of sex gametes (egg vs sperm) with the physiological expression of the underlying genetic makeup, and also combining it with the judgements humans as a society have made on how each sex looks and behaves---what makes a male a man or a female a woman. Phenotype is the physical outcome of the genotype an individual starts with, where the genetic interaction and womb environment and even early childhood take the original two flavors and spread them into a spectrum. Genital size and shape, limb dimensions, body shape, all start from the same source and take infinite paths from there. It's a fool's errand to try to narrow down exactly what marks an individual as belonging to one category or another, because while the source is simple (ish), it's only the beginning of development and all we see is the end.

That's also entirely leaving out the societal influences, what non-physical traits are assigned to each sex and the relative value associated with them.

None of what you're referencing here is considered a DSD condition.

Emily's Cat 29th November 2021 12:53 PM

@Louden Wilde

I've run across people bringing up "true hermaphroditism" as an argument for sex being a "spectrum". I've looked into it as best I can, and still end up confused, because I don't have the necessary technical background.

Is it possible for someone with ovotesticular disorder to simultaneously produce functional sperm and functional ova? I have difficulty envisioning how that might work, given that the levels of testosterone needed for sperm production would likely destroy eggs... and the reduction of testosterone needed for healthy egg release would likely be insufficient to produce sperm.

There's the hypothetical case of a chimera who ends up with one fully developed ovary and one fully developed testicle... but has that ever been observed?

Louden Wilde 30th November 2021 09:51 AM

Quote:

Originally Posted by Emily's Cat (Post 13667444)
@Louden Wilde

I've run across people bringing up "true hermaphroditism" as an argument for sex being a "spectrum". I've looked into it as best I can, and still end up confused, because I don't have the necessary technical background.

Is it possible for someone with ovotesticular disorder to simultaneously produce functional sperm and functional ova? I have difficulty envisioning how that might work, given that the levels of testosterone needed for sperm production would likely destroy eggs... and the reduction of testosterone needed for healthy egg release would likely be insufficient to produce sperm.

There's the hypothetical case of a chimera who ends up with one fully developed ovary and one fully developed testicle... but has that ever been observed?

Good question -
there's a case of a person from the early 70s who reproduced as a male but ultimately was found to have an ovary (& fallopian tube) with what looked like some developing oocytes. He had come in complaining of impotence (note he had two children - and the analysis of his sperm suggested normal fertility). At earlier medical exams he had been thought to have one undescended testis. They decided to do an exploratory surgery and then found the female tissue.

Microscopy showed that he was mosaic - ~30% of the cells appeared to be XX - including all those surveyed in the rudimentary female reproductive tract. So - person was almost certainly a chimera (they obviously didn't do genotyping the way we would now). But he was clearly only able to reproduce as a male (they note his impotence went away after they removed the female reproductive tissue).

And that gets to what I think is the definitional problem - in other species we use the term to mean having multiple potential reproductive roles - whereas the human literature refers to anyone with some tissue from both reproductive tracts as a hermaphrodite. Meaning- it's clear there's no class of humans (or any mammal) that can reproduce as both female and male.

ETA- pdf is too big to attach (though only 915kb) - any suggestions?

Also- shouldn't this thread be under the science-math-med-tech subheading?

d4m10n 30th November 2021 10:14 AM

Quote:

Originally Posted by Louden Wilde (Post 13668191)
Also- shouldn't this thread be under the science-math-med-tech subheading?

Fair point. [emoji117]

Earthborn 5th December 2021 01:36 PM

Quote:

Originally Posted by d4m10n (Post 13663259)
I've seen the Quigley scaleWP and that convinces me that genital morphology is indeed a spectrum,

Which is what people mean when they say that "sex is a spectrum".

Quote:

but I tend to think of sex as an evolutionary adaptation which facilitates reproduction of individuals.
When some claim that "sex is a spectrum" they are referring to the sex of an individual, not the concept of sexual reproduction in a species.

d4m10n 5th December 2021 01:42 PM

Quote:

Originally Posted by Earthborn (Post 13672599)
Which is what people mean when they say that "sex is a spectrum".

Would those same people say polydactyly makes number of fingers a spectrum, or would they be okay with generalizations like "Humans have ten fingers and ten toes."

Earthborn 5th December 2021 02:25 PM

Quote:

Originally Posted by d4m10n (Post 13672605)
Would those same people say polydactyly makes number of fingers a spectrum,

Probably.

Quote:

or would they be okay with generalizations like "Humans have ten fingers and ten toes."
They wouldn't be okay with a claim that the number of fingers and toes a person has, is a completely binary choice of 0 or 40.

Elaedith 5th December 2021 02:58 PM

Quote:

Originally Posted by Earthborn (Post 13672599)
Which is what people mean when they say that "sex is a spectrum".

Then they are conflating sexual characteristics with sex, which is silly, and would never be done were it not for wanting to distort science to fit an ideological goal. Does having larger genitals make a man 'more male'?

Quote:


When some claim that "sex is a spectrum" they are referring to the sex of an individual, not the concept of sexual reproduction in a species.
The sex of an individual is based on having a reproductive system for the production of one of two types of gamete.

d4m10n 5th December 2021 03:46 PM

Quote:

Originally Posted by Earthborn (Post 13672649)
They wouldn't be okay with a claim that the number of fingers and toes a person has, is a completely binary choice of 0 or 40.

Sort of a silly analogy, but let's run with it. The number of oocytes at birth is usually either zero (males) or around a million (females). Individuals with more than zero oocytes can nearly always be classified as female, even if sexual morphology is atypical.


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