I haven't actively looked for studies in this but I'm curious if these "fundamental" interests are somewhat partially driven by how society or people view them based on their sex. That is, get in them interested in certain things based on what the individual/society believes that their sex "should" be doing.

These kind of things could certainly push people towards a certain interest.

Then again, this is a nature/nurture talk. I personally find it hard to believe that women "naturally" prefer going into nursing compared to men - without sarcasm, I think the lack of male nurses is part due to how society views "men" in the nursing field which is steeped in sexism (i.e it's a "girly" job only for women).

I believe it was often the opinion at the time that nursing roles were delegated to women, societal opinion was veered towards that and you have kind of a "generational opinion/bias" forming. Nowadays, you (not you; in general) see the ratio is still quite different but you think this is now due to fundamental interests instead of any form a social (something; missing a word here). Anyhow this is all just speculating off of my opinion