Male and female incarnations equally indispensable: Since male and female incarnations are equally necessary for Self-knowledge, it is not right to look upon one as being more important than the other. Though there are differences between the nature of the respective facilities afforded by them, they are both indispensable. The soul must go through male incarnations as well as female incarnations if it is to have that richness of experience which is a condition of attaining the realization that the soul, in itself, is beyond all forms of duality-including the accentuated duality based on sex.
Unity of subject and object: Before the soul is set free from all sanskaras, it assumes numerous male forms and numerous female forms. If the soul were to incarnate only in male forms or only in female forms, its experience would remain one-sided and incomplete. The duality of experience can be overcome only through understanding, and the understanding of experience is only partial as long as it moves within the limits of only one of the two opposites. Unity of the subject and object of experience is unattainable as long as there is in the object any aspect or element not fully covered by one’s own experience; and this applies particularly to sexual duality.
-Discourses 7th Ed., p324