In the Judeo-Christian perspective, the theme is "very significant and emerges in the tradition’s reading and interpretation of some fundamental Biblical texts," from Plato's Banquet to the Book of Genesis, especially taken into consideration by the Cardinal. "While in the former the sexual difference is seen as a punishment that weakens man so that he cannot come closer to the gods, thus leading to man's fall from an almost divine level into defenseless slavery; in the Bible, conversely, the difference is precisely where God inscribes His action and His image." At the same time, "it is also important to point out another dissimilarity between Plato’s story and Scripture: while in Plato, a man and a woman, when they join, form a full, self-sufficient being, in the book of Genesis the union of man and woman does not lead to completion, and it does not close them in on themselves, because precisely their uniting opens them to the greater presence of God."

It is "God’s presence within the union between a man and a woman that helps us to consider the meaning of their complementarity. [...] The union of male and female is not complementary in the sense that it produces a full self-sufficient being, but in the sense that their union reveals how they are intended to help one another on the path towards the Creator. The way in which this union always refers beyond itself becomes evident when children are born. The union of the two, in 'one flesh', is present precisely in the one flesh of those that are generated by that union. This confirms that complementarity also means overabundance, a source of newness."