The family is a reflection of the Trinity as a communion of Persons.  Life is love-giving and Love is life-giving.

The Holy Spirit who is  Life, eternally proceeds from the unimpeded Love between the Father and the Son. In a similar analogous way, a child is the love between his father and his mother.  Life is neither ‘made’ (as with in vitro fertilization) nor impeded (as in contraception), but proceeds from the act of love, which is inherently unitive and procreative. Life-giving love is a reflection of God’s Trinitarian Life – as Lover, Beloved, and Love.

Meditate well on the meaning of this mystery and you will come to understand the inseparability principle —  the bedrock moral principle that states one may never intentionally separate the unitive from the procreative meanings of love, the two inseparable dimensions of life that cannot be ruptured.

Two common ways this is done today:

In vitro fertilization attempts to bypass union to ‘make’ life, while contraception attempts to unite while impeding procreation.  Simply put, one seeks life without (the act of) love, while the other seeks love without life.  Without union, human life is manufactured or ‘made’ through the instruments of technology, not begotten of the act of love between spouses. When intentionally thwarting procreation, sexual union is reduced to objectively using each other for pleasure’s sake, not a full self giving and receiving of each other.  This is not love.  This does not image God.

While there are many sincere reasons people seek to rationalize separation of the unitive from the procreative aspects of love, doing so is an objective moral disorder that is contrary to love.  Such a rupture of life from love deforms and desecrates God’s image on earth.