Countless phenomena of life will become clear to us if we think of human nature as the working together of two polar opposites. In the man the masculine pole works outwards and the feminine lives more inwardly, while in the woman the opposite holds true.
Spiritual science however also shows us a deeper reason why a masculine quality is to be found in the woman and a feminine in the man. Spiritual science speaks of how human beings strive after ever greater perfection, through many lives. Our present life is always the result of a previous one. Thus as we proceed through many lives, we experience both male and female incarnations. What arises in this way may be expressed as the effect of those experiences gathered on both sides in earthly life.
Whoever is able in this way to look more deeply into the male and female natures knows that the more intimate experiences of the two sexes are very different, and must be very different. Our entire earth existence is a collection of the most varied experiences. However, these experiences can only become comprehensive through their being acquired from the viewpoint of both sexes. […] So long as one merely looks at the physical body little can be understood. The spiritual lying behind must also be recognised.
Source: Rudolf Steiner – GA 56 – Man and Woman in Light of Spiritual Science – Munich, 18th March 1908