No, (3) is insane because it implies that biologically-driven preferences can change dramatically in just a few decades.
> You've defined any non-biological change in preferences as sexism.
That's (2), not (3). And I'm not sure what else to call socialization that discourages a particular gender from pursuing a high-reward field like computer science. I'd certainly call it sexism for men to be socialized to avoid well-paying jobs in nursing.
> they have self-selected into certain fields that appeal more to them than others do.
Why do they prefer to forgo a field like computer science or engineering? Is it because it's mathematically intensive and detail oriented? In that case, how do you explain half of all accountants being women? Is it because women care less about making lots of money? But plenty of women go into medicine and law. The "women prefer to forgo a popular, well-paying field" theory only makes sense if you don't bother to ask "why?"
And it's hilarious that you keep criticizing me for not offering evidence, when your whole position seems rooted in "women prefer certain fields, because [???]". Seriously, what goes in that box?