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This is the improved thread on the five factors of sex determination, this thread will also be tackling something a little different that I've hinted at for a bit now that I've done some reading and research.
So what are the five factors of sex determination?
Genitalia [ Penis / Clitoris ]
Karyotype [ Whether SRY is present or not ]
Gonads [ Testicles, Ovaries, Ovotestis ]
Internal Reproductive Structures [ Organs, Mullerian/Wolffian Ducts ]
Natural produced hormones
Genitalia [ Penis / Clitoris ]
Karyotype [ Whether SRY is present or not ]
Gonads [ Testicles, Ovaries, Ovotestis ]
Internal Reproductive Structures [ Organs, Mullerian/Wolffian Ducts ]
Natural produced hormones
Typically in the case of 99.8% of live births, individuals can be properly sexed based on genitalia alone. The reality of this is? If we discarded regressive societal baggage and didn't use the prader and quigley scales to propose correction? You could accurately determine all.
So, let's start with this disgusting scale, So here's the interesting thing. You'd think IV or at least V is male right? Well actually, they aren't. The female reproductive organs are still developed and the skin where the scrotum would be, are just empty sacs of skin.
Yes this is a specific case but if we're going to explain genitalia right away, I need to utilize this. This is generally what happens in severe cases of CAH, where the urethra becomes displaced toward or into the clitoris and the vagina can become fused with the urethra.
However even in that diagram you can see something, all through "F" to V, they have a uterus. Not only that but there are differences between the clitoris and penis that could settle this as well. CAH girls tend to grow into their genitals, they don't stay "that" big as adults.
Karyotype in terms of XX = Female, and XY = Male is a dated statement but even then it's fairly accurate with a 99.8% accuracy rate, similar to observed genitalia. Interesting isn't it? Well that's because XO, XXY, XXYY, XYY, you name it are not "typical karyotypes."
On top, you'll notice that as humans we always have a X and a Y and a X is always our first sex-based chromosome, due to the breaking down and nature of the Y that a Y monosomy will result in fatality. It's an error in meiosis. X must always be there.
https://onlinelibrary.wiley.com/doi/pdf/10.1038/npg.els.0005545
https://onlinelibrary.wiley.com/doi/pdf/10.1038/npg.els.0005545
Much like there are issues with a trisomy on the 23rd pair as well. This includes Klinefelter [XXY male], XXX - but seems to not include XXY Female variants but we don't know for sure. Triple X Syndrome for instance comes with numerous health issues. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2987225/
So if XX and XY are dated and disclude so many intersex conditions, how do we get around that? Well the answer to that conundrum is simple! The SRY gene and its presence, not to mention the leading X chromosome itself. Although it will obviously have its own issues.
SRY comes in 4 states.
Negative, as in not present.
Positive, as in there and fully working
Fragmented, as in remnants of the SRY gene is there, seen in rare ovotesticular cases
And lastly:
Mutated - Meaning the SRY gene is mutated and functions differently, despite being present
Negative, as in not present.
Positive, as in there and fully working
Fragmented, as in remnants of the SRY gene is there, seen in rare ovotesticular cases
And lastly:
Mutated - Meaning the SRY gene is mutated and functions differently, despite being present
I'll just be dropping varying cases about the oddity of SRY here.
https://jmg.bmj.com/content/36/6/452
https://www.cell.com/ajhg/fulltext/S0002-9297(09)00113-X
https://pubmed.ncbi.nlm.nih.gov/11173857/
https://www.longdom.org/open-access/a-new-female-case-with-47xxy-karyotype-and-sry-2167-0250-1000157.pdf
https://pubmed.ncbi.nlm.nih.gov/16846094/ https://www.fertstert.org/article/S0015-0282(08)01497-0/pdf
https://jmg.bmj.com/content/36/6/452
https://www.cell.com/ajhg/fulltext/S0002-9297(09)00113-X
https://pubmed.ncbi.nlm.nih.gov/11173857/
https://www.longdom.org/open-access/a-new-female-case-with-47xxy-karyotype-and-sry-2167-0250-1000157.pdf
https://pubmed.ncbi.nlm.nih.gov/16846094/ https://www.fertstert.org/article/S0015-0282(08)01497-0/pdf
So here's a general gathering of every human karyotype I know of and which sex they belong to. There will be similarities but the conditions are drastically different, it's specifics that won't be gone into here in this thread but ties to the five factors.
Generally in regards to SRY's status? It's a mostly flawless process but I wouldn't solely rely on it. Thanks to the second type of De La Chapelle Syndrome as well as some rare mosaic cases we know that the SOX9 gene can cause with duplication. It'd be a 99.99925% accuracy rate.
Gonads are kind of tricky but not as tricky as that pesky SRY gene. So gonads are a bit of a "gotcha" loved among many, because it is possible for a body to have two different types of gonads housed within it, but the question of functionality comes into play at this point.
Streak Gonads [Tissue that is often safer being removed, does nothing.]
Ovaries [The general female gonad]
Testicles [The general male gonad]
Ovotestis [Tissue that has a varied appearance, it either is dysfunctional or produces strictly ova or sperm. Their composition can vary]
Ovaries [The general female gonad]
Testicles [The general male gonad]
Ovotestis [Tissue that has a varied appearance, it either is dysfunctional or produces strictly ova or sperm. Their composition can vary]
Now there are some interesting cases here, such as a favorite: AIS, or Androgen Insensitivity Syndrome. The testicles appear to work properly, but they don't at the same time. Due to a mutation on the X chromosome those with AIS cannot process the androgens produced by the gonads
This resistance can vary from low, meaning it's negligible and leads to a typical male phenotype, to complete rejection being a typical female phenotype or rather sex-rejection class. However C/AIS gonads typically do not work in production of sperm, nor can they.
Typically the gamete your body produces is an obvious tell. You produce sperm? You're male, ova? Female. However like AIS, the gonads are dysfunctional and tell us nothing. On top of that you have the process of aromatase leading to the sex-rejection. https://pubmed.ncbi.nlm.nih.gov/1769135/
There've been cases of AIS women and girls being discovered to have uterine tissue, as well as an article claiming a woman with AIS managed to gestate through IVF due to said uterine tissue.
Outside of gray cases it's usually easy to mark a determination for male or female on the gonads, even within intersex cases. Ovotestis for instance can only successfully produce one of the two gametes into adulthood[Or become dysfunctional], meaning a support for ova or sperm.
Gonads are usually pretty simple determinants until you get to cases where the body resists the sex hormone produced, arguably altering it even. This results in the part in question going from functional to non-functional. Arguably accurate in 99.982% of cases.
Reproductive Structures is typically a rather straight forward one but there's a certain exception you've most likely heard of. It's referred to as PMDS or rather Persistent Mullerian Duct Syndrome. It's a condition where the Mullerian Ducts in a male do not dissolve.
Typically if Wolffian structures are fully developed and the paths are set for testis determination and function, then you have a male determination without question. However, there are cases where arguably both can be present. The said rare condition mentioned above.
However these uterus that remain in these bodies tend to be dangerous to keep, having one of the highest malignant transformation rates. Little is known about the impacts of keeping a functional uterus and the like in PMDS and it is highly discouraged once it is discovered.
PMDS is a topic I personally prefer to avoid due to its sheer rarity but realistically speaking you can't deny the Mullerian structures are there but are they usable alongside the Wolffian? Absolutely not. PMDS is a male condition for a reason, many even father children.
Typically reproductive structures can also be a tell for one's sex determination and like I said, all five methods aren't even necessary for 99.982% of the population which includes numerous intersex cases. Only the rarest of the rare require all these tests.
Hormone production is rather straight forward, what hormones does the body naturally produce. Does it support leading into more male-typical characteristics or more female-typical characteristics. Obviously there are variations and differences in the level of sex hormone produced
This factor isn't discredited because of producing higher then average testosterone, or estrogen in other cases. This one doesn't really need explaining but once again we'll point at the function of aromatase, especially within those who have AIS where testosterone is converted
You'll find that C/AIS is not a favored case in these circumstances due to the complexity associated with the condition. It isn't outright male, but these cases can't be argued as sex reversal either at that level. It certainly isn't proof of a sex spectrum either.
However it can't be denied that aromatase in these cases leads to producing female hormones on their own, especially in CAIS cases and sometimes in PAIS. However obviously in MAIS cases the individual is still an obvious intersex male with minor undermasculinization.
So now that we've gone over all five, I'll bring attention to the experience of an endosex father and his intersex child regarding the tests ran in these particular cases. https://twitter.com/EndosexD/status/1365388859664695308
Generally speaking genitalia being the first thing observed is still the best approach forward. Especially if you discard our harmful societal impressions of implying a penis isn't "enough" or a clitoris is "too much" - Rather the harm of "lesser/greater" in a nut shell.
So in order - Genitalia -> Karyotype[SRY STATUS] -> Gonad Tissue -> Reproductive Structures&Ducts -> Hormone Levels and if the baby is a female and managed to need most of these tests, she should be tested for salt wasting, as it can be fatal if not caught.
Generally speaking if you were to discard the societal baggage, kick those horrible scales to the curb and use what knowledge we have to differentiate penis and clitoris, genitalia alone would be stupidly high in terms of its accuracy with karyotype generally being confirmation
Obviously though, following through with the other factors to confirm if any irregularities with SRY are detected would continue to be advised. We should be promoting the normalizing and acceptance of intersex bodies, not arguing that we're not male or female enough.
That's exactly what the Quigley and Prader scales do anyways, imply that intersex children aren't male or female enough and should be "corrected."
Remove shame off intersex bodies, discourage IGM and make our bodies acceptable as our sexes. That's what we should be doing.
Remove shame off intersex bodies, discourage IGM and make our bodies acceptable as our sexes. That's what we should be doing.
This was a monster of a thread and it took me awhile to gather everything I needed for it. Hopefully it serves its purpose - People need to know that we're far beyond the 1950s now and really with our present knowledge if we used it right? Genital observation works just fine.
