“Since “biological sex” is actually a social construct, those who say that it is not often have to argue about what it entails. Some say it’s based on chromosomes (of which there are many non-XX/XY combinations, as well as diversity among people with XY chromosomes), others say it’s genitals or gonads (either at birth or at the moment you’re talking about), others say it’s hormone levels (which vary widely and can be manipulated), still others say it’s secondary sex characteristics like the appearance of breasts, body hair and muscle mass (which vary even more). Some say that it’s a combination of all of them. Now, this creates a huge problem, as sex organs, secondary sex characteristics and hormone levels aren’t anywhere close to being universal to all men or women, males or females. Those who claim that sex is determined by chromosomes must not realize that sex is assigned at birth not by chromosomes, not even by gonads, but by genitals. In fact, the vast majority of us never learn what our sex chromosomes are. Sex isn’t something we’re actually born with, it’s something that doctors or our parents assign us at birth. So if sex is determined by genitals, they must be clearly binary and unchangable, right? Wrong. Genitals can be ambiguous at birth and many trans people get gender confirmation surgery to change them. Neither chromosomes nor genitals are binary in the way that “biological sex” defenders claim they are, and the vast majority of measures by which we judge sex are very much changable.”
Oy, please do try not to be an idiot.
In humans, sex is determined by the presence of the sex-determining region Y protein (SRY, for short). In individuals with non-mutated sex (X / Y) chromosomes, SRY genes are carried on the Y chromosome. For the vast majority of humans, this means that individuals with the XX karyotype will express a typical female phenotype, and individuals with the XY karyotype will express a typical male phenotype.
It is possible for a human to have monosomy X - only an X chromosome, associated with Ullrich-Turner syndrome - but not monosomy Y, because the X chromosome is required for a fetus to be viable. Individuals with monosomy X will express female traits due to the lack of SRY genes.
It is also possible for humans to have trisomies, so long as at least one X chromosome is present: XXY, XYY, and XXX. Higher order polysomies, where four or even five sex chromosomes are present, are also possible. In all cases, if at least one Y chromosome with a properly functioning SRY gene is present then the individual is male, and if there are no Y chromosomes the individual is female.
Note that both polysomies and monosomy are unusual, with some variations being exceedingly rare. Most of these mutations are associated with physical and/or mental problems, although XXX women and XYY men usually don’t face any problems (and many aren’t diagnosed).
How about you try science next time, instead of spouting fountains of vacuous drivel.