> The research community does not have a better explanation for the disparity than social bias
That's not really true. There is a lot of research showing that men and women have different interests and make different life choices, and that these choices impact career demographics. One of the most well-researched differences is that men tend to be more interested in "things", especially mechanical things, and women tend to be more interested in "people".
Here is a journal article from Frontiers in Psychology that investigates how these differences-in-interest impact STEM field participation: "All STEM fields are not created equal: People and things interests explain gender disparities across STEM fields" (1):
> In the current study, we investigated the gender differences in interests as an explanation for the differential distribution of women across sub-disciplines of STEM as well as the overall underrepresentation of women in STEM fields. (...) We found gender differences in interests to vary largely by STEM field, with the largest gender differences in interests favoring men observed in engineering disciplines (d = 0.83–1.21), and in contrast, gender differences in interests favoring women in social sciences and medical services (d = −0.33 and −0.40, respectively).
> Importantly, the gender composition (percentages of women) in STEM fields reflects these gender differences in interests. The patterns of gender differences in interests and the actual gender composition in STEM fields were explained by the people-orientation and things-orientation of work environments, and were not associated with the level of quantitative ability required. (...)
Some studies show that these things-vs-people differences begin to manifest extremely early in life, before humans could be influenced by social factors. One famous study of this phenomenon is "Sex differences in human neonatal social perception" (2):
> Sexual dimorphism in sociability has been documented in humans. The present study aimed to ascertain whether the sexual dimorphism is a result of biological or sociocultural differences between the two sexes. 102 human neonates, who by definition have not yet been influenced by social and cultural factors, were tested to see if there was a difference in looking time at a face (social object) and a mobile (physical-mechanical object). Results showed that the male infants showed a stronger interest in the physical-mechanical mobile while the female infants showed a stronger interest in the face. The results of this research clearly demonstrate that sex differences are in part biological in origin.
It is also known that testosterone levels affect decision-making and career choices, and that women tend to be more financially risk-averse than men. Since men's testosterone levels tend to be much higher than women's, and since men are less risk-averse, that results in demographic differences. For an investigation of this, see the article "Gender differences in financial risk aversion and career choices are affected by testosterone" (3). For another study on sex and brain differences see (4). There is a lot of research out there exploring the differences between men and women, and how those differences play out in our lives.
Every person should be supported in choosing whatever career interests them, and should not be judged based on demographics. I'm not advocating for any kind of discrimination. I am just observing that even with total equality of opportunity, if there are biological trends in interest differences, then we will see differences in overall job demographics.
(1) https://www.frontiersin.org/articles/10.3389/fpsyg.2015.0018... (2) https://www.math.kth.se/matstat/gru/5b1501/F/sex.pdf (3) https://www.pnas.org/content/106/36/15268.full (4) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030621/