Male and female are two contradictory, inseparable and eternal parts of this world. Also, the dispute continues forever: who is first, who is more important, who is smarter, who is stronger... Now openly, now secretly we are winning from each other the right to this world. The world is bursting at the seams, either from male chauvinism, or from female feminism, or from unisex that erases everything. Meanwhile, both warring sides dream - you won’t believe it - of love! Is there another way? There is and it is called the “principle of complementarity”, based on the fact that a man and a woman are fundamentally different beings: physically, mentally and intellectually - completely different. And there is no point in them competing. Let’s go through a spiral from biology, through the psyche to the capabilities of the mind and see where we are strong and where our weaknesses are, and how a man and a woman can not fight, but cooperate. And not to be afraid of each other, for “he who fears in love is imperfect”—His world is society, hers is nature.—She gives birth, he protects.—He builds, she revives.—He thinks, she sees.