I've not been able to find any scientific sources which tell us how to discern the first bolded case from the second one.
Then you can't have looked very hard. This took me less that 10 seconds to find
Find out about androgen insensitivity syndrome (AIS), a rare condition that affects the development of a person's genitals and reproductive organs.
www.nhs.uk
For those who affirm "We can ALWAYS ultimately determine whether an individual human is male or female"
I'd be interested in knowing how you do this for PAIS individuals.
There are 2 main types of AIS, which are determined by how much the body is able to use testosterone.
These are:
- complete androgen insensitivity syndrome (CAIS) – where testosterone has no effect on sex development, so the genitals are entirely female
- partial androgen insensitivity syndrome (PAIS) – where testosterone has some effect on sex development, so the genitals are often not as expected for boys or girls
PAIS is usually noticed at birth because the genitals appear different.
CAIS can be more difficult* to spot, as the genitals usually look like those of any other girl. It's often not diagnosed until puberty, when periods do not start and pubic and underarm hair does not develop.
* Please note:
"can be more difficult" ≠
"impossible"
"Sex rejection takes place" seems fairly question begging, unless we are told which observable factors led someone to that conclusion in any given case. We know that gametes aren't breaking the tie here, so what really is?
You did not address how to tell that "sex rejection" has happened, or even give us a link to a publication (non-meme) which uses that language.
A series of flow charts showing the steps of sex development for typical males and females and a variety of DSDs.
www.theparadoxinstitute.com
Direct link to document here...
WARNING: PDF File size 937kb
Take particular note of Panel 14
You also did not address why you said CAIS individuals are male
while the meme chart (which you support) says otherwise female.
I modified the
CHART especially for you, and I will explain it like I did before, but this time in baby steps so that you can follow along
WRT above:
https://static1.squarespace.com/sta...03/Sex+Development+Flow+Charts+2024.08.05.pdf
An individual can end up becoming either male or female, depending on what happens with a specific gene - a DNA-binding transcriptor that regulates gene expression. This gene is known as the
"Androgen Receptor" (AR) gene, which has several functions, one of which is critical to the development and maintenance of the male phenotype.
When a normal individual's AR gene does fire, that individual will develope into a
male
When a normal individual's AR gene does not fire, that individual will develop into a
female
In some individuals, specifically individuals with karyotype 46:XY SRY+, the AR does not fire correctly, and the individual can develop into either a male or a female depending on other factors in the gene itself. When that happens, if the changed factor in the gene is a specific type of mutation that prevents androgen binding, the body does not respond to testosterone, and this will lead to that individual developing with female genitals. This is
"sex rejection" - the 46:XY SRY+ individual rejects the genetic information telling it to develop
male
genitals, and so it reverts to the default pathway and ends up being
female
despite the fact that they have
XY chromosomes.
However, there is another possibility. The AR fires, but the specific of mutation doesn't entirely prevent androgen binding, it only limits it, and the body does respond to testosterone but ineffectively, and this will lead to that individual developing with male genitals. The sex development path is not entirely rejected but it is limited resulting in underdevelopment of gonads and charactistics such as less facial hair than usual, less or lack of body hair, smaller muscle mass, a less prominent Adam's apple and a high-pitched voice. In some cases, gynecomastia (breast development) is seen around puberty.
So, we end up with a possibility of an 46:XY SRY+ individual being male or female, entirely depending on the type and seriously of the mutation on the AR gene. But most importantly, they ALWAYS follow a pathway that leads to development as a male or a female. THERE IS
NO PATHWAY THAT LEADS TO A THIRD SEX, AN INDETERMINATE SEX OR NO SEX AT ALL.
Now this is my understanding of how this stuff works. As I said earlier, I am not a biologist, but
@Louden Wilde and
@Rolfe are, and I expect they will correct me if there are any glaring errors in my understanding, or if there are any important details I have left out.
By George, I think you've got it!! 
"Don't confuse me with facts, my mind is made up", amirite?
