We call it the assimilation instinct. Not only is self-assertion an assimilation instinct in the ontogenic sense, but in the phylogenic sense as well. Every living thing tries to recreate its likeness by means of its seed from the universal whole, to mold all there is in its own image. A grain of wheat sends out roots in order to fashion a new grain of wheat from earth, sunlight rain and air. The cornflower, too, extorts its blue blossoms from earth, sunlight rain and air.
Coral strives to transform the whole ocean into coral islands.
Throughout the slow development of the earth's crust a crystal tries to change everything around and about into crystals. The man's seed is forced into the body of the woman and forces her to nourish the man's likeness with her blood. The life principle hidden - within her lets her mold the seed according to her features. Results a struggle between the instincts of assimilation. The characteristic qualities of both find themselves locked in embrace within the new being.