That is a little abstract of course, as you would expect from a theoretical physicist, but its really quite simple. He poses the question of what the purpose could be for our ability to understand a great deal about the universe. He made and sustains the universe in such a way that it has evolved beings able to relate freely back to himself. It is for this purpose that humankind consists of sexual beings, in the sense that just as in the power of the Spirit the ordinary stuff of bread and wine become for us in the Eucharist the food of our pilgrimage, so the ordinary stuff of human relationships, has come to be used by God as a means of grace for us to relate to him. Through our capacity to know each other as men and women we develop the spiritual capacity to know God.
Religion necessarily has a lot do with sex.
So the proper use of the sexual nature of people helps them to fulfil their destiny of knowing their Creator. So we glorify God in the body as we strengthen our loyalty to Christ, to whom we belong, who bought us with a price. Glory be to him.