The reasons for using NFP go beyond biology. Understanding the holiness of the marriage covenant is rooted in the beauty of God’s commands. “What we do with our bodies expresses our deepest held convictions about ourselves, God, the meaning of love, and the ordering of the universe. When the Church’s sacramental view of the body is taken seriously, we understand that sexual union is not only a biological process, but a profound theological process: "This mystery is a profound one, and I am saying that it refers to Christ and the Church" (Eph. 5:32). 

West, C. (2003)”God, Sex, and Babies: What the Church Really Teaches about Responsible Parenthood. This Rock 14, no. 9 (November),

                                                       "Pope St. John Paul II said that the human body is representative of God and all his mysteries. God uses our bodies to reveal the truth of himself. Jesus teaches us the meaning of life is in loving one another: "Love one another as I love you" (John 15-12).

How did Christ love us? He gave up his life for us. God's love for us is made flesh in Jesus Christ. Christ's love is the reality of the body. Thus, in the gift of our bodies to one another, we act on our love as Christ loved us. Married love is different from any other kind of love. By the very nature of the two becoming one, this kind of love is ordered toward God and one another; creating new life together is cooperating with God's design. Sexual acts between husband and wife are representations of God's love for his creation. God's love for us is never sterile". Throughout his pontificate Pope John Paul II desired to integrate the scientific study of personal relationships with the revelation of God’s plan for marriage. Recalling his reflections on the relationships of men and women, John Paul II spoke about how NFP methods enable a couple to remain open to God’s gift of life while accounting for the whole person by “accepting dialogue, reciprocal respect, shared responsibility and self- control.” (Familiaris Consortio 32) 

Barron, M.L (2009) "Natural Family Planning: A Catholic Approach" p.8-9. Liguori, Liguori, MO.

The Effect of NFP on Marriage

Although living with one's (and one's spouse's) fertility through the practice of NFP can at times be a challenge, there are numerous benefits that result. These benefits include the important understanding of how the body works and the peace of knowing that there are no medical side effects. Other benefits are those that strengthen marital life, such as increased communication, increased intimacy, renewed sexual desire and being open to new life. NFP also helps develop mastery over sexual urges rather than being controlled by them. NFP is morally and ethically accepted by most cultures and religions. Many couples that use NFP report an increase in spiritual well-being and a sense of being open to God's will in their lives

The greatest benefit is that users are encouraged to more fully learn and imitate the love of Christ through the practice of NFP—a love that is free, total, faithful, and fruitful! 

Research Evidence

Researchers from Marquette University College of Nursing have conducted a study to identify the effects of modern NFP methods on marital dynamics. Couples were asked by the researchers as to whether the use of NFP had been helpful or harmful to their marriages. The open-ended questions were part of a longer questionnaire mailed to 1,400 randomly selected couples known to use NFP and reside in the United States.

The researchers found that 74% of the total 2,287 responses were positive and only 26% were negative. There were four positive themes identified (enhanced relationships, improved knowledge, enriched spirituality and method successes) and three negative themes (strained sexual interactions, worsened relationships, and method problems).

Some example responses under the positive theme of "improved relationships" not reported in the published paper are as follows:

Improved communication: "Since we speak about our fertility on a daily basis (my husband charts and asks my observations daily) NFP has helped our level of communication remain very deep and intimate and always above-board, open and honest."

Appreciated sexuality: "Our sexual relationship is incredible. I have no complaints and truly believe the periodic abstinence of NFP causes us never to get in a rut sexually."

Understand cycles and bodies: "[NFP was] helpful to understand PMS symptoms for myself and my husband because of our awareness of my cycle. Thus, helped keep our moods/reactions/issues in balance/in perspective."

Self Control: "About the time when you are ovulating is when you're most susceptible to having sex, because it is a natural time to be having sex, but on the other hand it teaches us self-discipline and… priorities."

Enriched spirituality: "It has helped my relationship with God which has positively affected my relationship with my spouse….I've come to know and love God all the more for learning His beautiful truth about the real…meaning of human sexuality." 

VandeVusse, L Fehring, RJ, & Hanson, L. (2003) Couples’ Views of the Effects of Natural Family Planning on Marital Dynamics, Journal of Nursing Scholarship, 35, 171-176.)