Economy-of-effort theory
The economy-of-effort theory is an idea in the study of humans and the study of men, women, and sometimes a third or fourth type of person.  Scholars use it to say why some groups of people give some work to women and other work to men.  In an economy-of-effort scenario, work goes to men or women (or some other gender role recognized by that culture) not because of differences in men's and women's bodies but because other things about that culture make it easier.