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#1 |
Philosopher
Join Date: Jun 2012
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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. |
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#2 |
Observer of Phenomena
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#3 |
Дэлво Δελϝο דֶלְבֹֿ देल्वो
Join Date: Jul 2008
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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.
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#4 |
Philosopher
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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.
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." |
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#5 |
Philosopher
Join Date: Jul 2013
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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. |
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#6 |
Critical Thinker
Join Date: Oct 2020
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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.
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#7 |
Philosopher
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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.
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#8 |
Critical Thinker
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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. |
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#9 |
Cowardly Lurking in the Shadows of Greatness
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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. |
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#10 |
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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. |
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#11 |
Critical Thinker
Join Date: Oct 2020
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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
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#12 |
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#13 |
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@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? |
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#14 |
Critical Thinker
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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? |
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#15 |
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#16 |
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#17 |
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#18 |
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#19 |
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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'?
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#20 |
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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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