God's crowning act of creation is man and woman. The complementarity of the male and female body is meant to be a sign of the innermost mystery of God-an eternal exchange of love, the Father, Son and Holy Spirit bound together in the Trinity. The sexuality of the human body as male and female is the visible sign of this invisible mystery revealed to us by God.

St Paul, borrowing the words of Genesis, says, "For this reason a man shall leave (his) father and (his) mother and be joined to his wife, and the two shall become one flesh." [
Eph 5:31] To this, St Paul adds, "This is a great mystery, but I speak in reference to Christ and the church." [Eph 5:32] Sexual intercourse is meant to be a sacrament, an earthly sign, of Christ giving up his body for his bride the Church. "This is my body given up for you". Christian marriage is a sign of the covenant between Christ and His Church. The marital act is to be a truthful sign of Christ's covenant love.

There are four characteristics of Christ's love:
1)        Christ's love is free. "No one takes it from me, but I lay [my life] down on my own." [John 10:18]
2)        Christ's love is total. "This is my body, which will be given for you" [
Luke 22:19].
3)        Christ's love is faithful. "I am with you always".[
Matt 28:20] "I will never leave you orphans". [John 14:18]
4)        Christ's love is fruitful. "I came so that they might have life and have it more abundantly." [
John 10:10] Christ blood is the new and everlasting covenant and on all God's covenants is the blessing of fruitfulness.

These characteristics are part of the wedding covenant we entered into on our wedding day. In the marital act, the words of the wedding vows become flesh-a sign of the love of Christ for his Church. Thus, the physical expression of love between spouses must be free, total, faithful and fruitful.

But if we can speak truth with our bodies, we can also lie. Is this act an authentic sign spoken in truth of God's free, total, faithful, fruitful love or not? Pope John Paul II writes: "we can speak of the moral good or evil in sexual relationships according to whether or not it has the characteristics of the truthful sign." [John Paul II, Theology of the Body, pp141-142] Is rendering the marital act sterile a truthful speaking of the language of the body as an authentic sign of God's love? It is not total because I withhold my fertility. It is not fruitful because I have rendered it sterile.

Contraception turns the "I do" of the wedding vow into an "I don't." The vows taken on our wedding day confirm the unitive and procreative teaching of the Church. We cannot say that faithfulness to our spouse does not require us to limit every act of intercourse to them alone; so also we cannot say that fruitfulness does not require all acts of intercourse to be open to life.

Catholics can remain true to their wedding vows and speak the language of the body as an authentic sign of God's love and limit the fruitfulness of the marital act through abstinence after serious consideration of the moral law and God's plan. Contraception is the choice to engage in an act of intercourse but render it sterile. This speaks the language of the body as a lie. Abstinence is the choice not to speak rather than to speak falsely.

Natural Family Planning, periodic abstinence, is licit because it is in keeping with the inseparability of the unitive and procreative nature of sexual intercourse as a renewal of the couples wedding vows. With NFP the pathway to life is still open to God's will. God's plan is at work. With contraception we take control and act as if we are God-a reprise of the original sin in the Garden of Eden.

You can hear a homily on the Church's teaching on Contraception here.