What's assigned on birth isn't a gender but sex
first of all, sex is not assigned. you don't assign someone a Y chromosome. gender can be and is commonly assigned at or before birth, when, for example, a couple decides to refer to their child as their son or daughter when the scans come in. i agree with you that it
shouldn't be assigned at birth and we should just do the medieval thing of not gendering children until the children themselves begin to understand what genders are, but as things are right now, people's gender are often assigned at birth, and being assigned a gender they don't end up identifying with is a common experience among trans people. in fact, it is the defining experience.
The tricky thing about gender and gender roles is that evolutionary effects have ingrained that so much into both our biology and society at large (look up the field of evolutionary biology, it's interesting) that I'm almost certain they are here to stay at least until biomods at the level of TiTS come along. If you don't believe me, look at Scandinavia. They have abolished almost every barrier that would affect a woman to choose the profession they want and they have the least diverse gender distribution in their workforce in the world, presumably because it's an affluent society and no woman is forced to become an engineer or technician just to put food on the table so they are free to choose professions more in line with their psychological and hormonal makeup.
any time people bring up evolutionary psychology i have to brace myself a little, doubly so when they confuse it with evolutionary biology. doing my best to be concise, psychology doesn't have fields, it has approaches. the evolutionary approach stand in equal grounds with the cognitive and sociocultural approaches. some behaviors, such as morning sickness, are more easily explained by one approach than the others, but broad topics such as gender is studied with all 3 approaches in mind. human behavior can't be simply attributed to any one factor and all three approaches must be examined in order to get the full picture.
in Margret Mead's book
Sex and Temperament in Three Primitive Societies, published in 1935, Mead described 3 tribes with vastly different gender roles. one where the men and women displayed so-called "traditional" traits, where men are aggressive and domineering and the women mellow and submissive, another where it is the reverse, and one more where both genders are competitive and aggressive. in other unrelated studies, traditional identities outside of male and female have been found as well in cultures through out history, most notably in the Philippines where many local words describing third traditional gender identities exist in various tongues.
there is undeniably is an evolutionary and biological aspect to gender roles and identity. but the existence of cognitive and sociocultural aspects are equally undeniable. available scientific evidence does not support the idea that our current gender roles are the inevitable result of biology rather than one of many possibilities a society could arrive at based on a variety of factors. to say that our binary system is created by some force of nature would imply that all of its exceptions were somehow mistakes, and further imply that there is a purpose or goal to evolution from which mistakes can deviate from. both of these statements display a lack of reflexivity and would get you some disturbing packages from less than professional biologists and psychologists. the more reasonable assumption is that our idea of what is natural and "simply biological" is heavily influenced by the biases stemming from the euro-centric roots of modern science. this is one of the core criticisms towards evolutionary analysis. further research is required to determine the extent to which biology affect gender roles in society.
in order for the Scandinavia example to hold water, it will have to operate under the assumption that there is zero cultural bias, contemporary or historical, in terms of gender role, and that Scandinavia is not influenced by cultures that may have said bias. only then could one attribute the entirety of their workforce imbalance to biological factors. it's...a naive assumption, to say the least. even in
the article itself, the phenomenon is attributed purely to the removal of economic factors. Scandinavian women could and likely still are motivated by historical cultural perceptions of how a woman should act and what roles they should play in society, even if all the hard barriers were gone.
Scandinavia isn't some isolated nordic paradise where no injustices or bigotry exist in the present or past and no words of such things come in from outside. even without systematic enforcement or economic incentive, cultural expectations can drastically impact behavior, as demonstrated by
Steele & Aronson's study on stereotype threat (steele lul), the result of which showed black students who hold negative stereotypes about their race perform noticeably worse overall than those who don't.
there is also evidence for behaviors being impacted by cultures outside of your own, as can be found in the existence of culture-specific disorders, symptom repertoires,
and their ability to spread to other cultures. if even disorders can spread across cultures, values and expectations are likely to as well.
until we can remove entirely other factors and examine biological factors by itself, conclusions like "women just don't like STEM due to their hormones" can't be made responsibly.
in other words, further research is required to determine the extent to which biology affect gender roles in society.
that last sentence is repeated, because it had to be. it's the type of line you'll find shockingly frequently in papers and essays. the academia of science doesn't draw solid "x because y" type conclusions. only pundits do so, either for an agenda or simply brevity. modern science operates under the knowledge that the system is a complex machine that's barely holding together, but is functional at its core. all the rusty joints and inefficient mechanisms will eventually break the machine down, and the job of a scientist is to replace parts when they creak, preserving slivers of truth and shaving away the untruth once enough evidence against them surfaces. this process is more formally known as paradigm shift. in sillier terms, scientists gave birth to a slime baby and are still trying to figure out what's the baby and what's the bath water. and ho boi does evolutionary psychology have a lot of bath water. the presumptions made about gender roles using evo psych are just that, presumptions, and ones with enough scientific evidence against them to justify being reconsidered.
in the interview at the end of the Scandinavian study article, a solution was proposed by one of the researchers to improve female representation in STEM:
“If governments want to increase women’s participation in STEM, a more effective strategy might be to target the girls who are clearly being lost from the STEM pathway – those for whom science and maths are their best subjects and who enjoy it but still don’t choose it,”
Note that it does not say "invest in biomods and give them cocks."
scientific literature has a history of being misconstrued by the general public and causing wide spread tragedy. the story of that MMR vaccine paper would be downright comical if the cover price wasn't paid in human lives. now that religion has dulled significantly as a political tool, science without critical thinking stand to do the most harm. i would stay wary when i hear claims this broad made with no internal criticism or reflection, and stay especially wary of making them.