> STEM is 90% men because of the way young people are socialized and then harassment, discrimination, and oppression that are endemic in the industry.

That's just a theory.

My theory is that it's not gender but differences in hormone balance, meaning circuits is same but without sufficient level of hormone needed to drive them, they won't function well.

Testing this theory should take much shorter time and less resources than yours. Another interesting yet controversial test could be whether raising the need for the circuits to work can change hormone balance.