The Republic by Plato Part 5 Page 14

Then let us put a speech into the mouths of our opponents. They will say: ‘Socrates and Glaucon, no adversary need convict you, for you yourselves, at the first foundation of the State, admitted the principle that everybody was to do the one work suited to his own nature.’ And certainly, if I am not mistaken, such an admission was made by us. ‘And do not the natures of men and women differ very much indeed?

’ And we shall reply: Of course they do. Then we shall be asked, ‘Whether the tasks assigned to men and to women should not be different, and such as are agreeable to their different natures?’ Certainly they should. ‘But if so, have you not fallen into a serious inconsistency in saying that men and women, whose natures are so entirely different, ought to perform the same