form of life in which a communion of persons is realized involving the use of the sexual faculty. “That is why a man leaves his father and mother and clings to his wife and they become one flesh” (Gen 2:24). Third, God has willed to give the union of man and woman a special participation in his work of creation. Thus, he blessed the man and the woman with the words “Be fruitful and multiply” (Gen 1:28). Therefore, in the Creator’s plan, sexual complementarity and fruitfulness belong to the very nature