From Pope St. John Paul II’s Apostolic Exhortation Familiaris Consortio (1981):
Fruitful married love expresses itself in serving life in many ways. Of these ways, begetting and educating children are the most immediate, specific and irreplaceable. In fact, every act of true love towards a human being bears witness to and perfects the spiritual fecundity of the family, since it is an act of obedience to the deep inner dynamism of love as self-giving to others.
For everyone this perspective is full of value and commitment, and it can be an inspiration in particular for couples who experience physical sterility.
Christian families, recognizing with faith all human beings as children of the same heavenly Father, will respond generously to the children of other families, giving them support and love not as outsiders but as members of the one family of God’s children. Christian parents will thus be able to spread their love beyond the bonds of flesh and blood, nourishing the links that are rooted in the spirit and that develop through concrete service to the children of other families, who are often without even the barest necessities.
Christian families will be able to show greater readiness to adopt and foster children who have lost their parents or have been abandoned by them. Rediscovering the warmth of affection of a family, these children will be able to experience God’s loving and provident fatherhood witnessed to by Christian parents, and they will thus be able to grow up with serenity and confidence in life. At the same time the whole family will be enriched with the spiritual values of a wider fraternity. Family fecundity must have an unceasing “creativity,” a marvelous fruit of the Spirit of God, who opens the eyes of the heart to discover the new needs and sufferings of our society and gives courage for accepting them and responding to them. A vast field of activity lies open to families: today, even more preoccupying than child abandonment is the phenomenon of social and cultural exclusion, which seriously affects the elderly, the sick, the disabled, drug addicts, ex-prisoners, etc.
This broadens enormously the horizons of the parenthood of Christian families: these and many other urgent needs of our time are a challenge to their spiritually fruitful love. With families and through them, the Lord Jesus continues to “have compassion” on the multitudes.
— Familiaris Consortio 41