Fertility is viewed as a reality to live, not a problem to be solved. Responsible parenthood is lived out within the structures which God has established in human nature. That is why the Church teaches that couples must not actively intervene to separate their fertility from their bodily union. To do so is to show disrespect for an important gift of the Creator. Sexual intercourse is not only eminently personal, between a man and a woman, but also has a public and even universal dimension.
Human reproduction orients sexual activity to the future of the world.
The public consequences of sexual intercourse are illustrated by the miracle of birth, and also through the public devastation wrought by sexually transmitted diseases. Only in a lifelong, committed, loving relationship, centered in Christ, can couples hope to fully experience the sacrament of life and love, i.e., marriage. Unconditional love is what marriage is all about.