Natural means of fertility control have been a life-long interest of mine. Even in the seminary (1942-47) I wondered why the Church didn’t intensively research and teach the theology and methodology of Natural Family Planning (NFP); then as now, birth control was an enormous problem.

Teaching marriage preparation courses for years at two Catholic colleges only enhanced my interest in NFP, as did giving many retreats for young married couples after the war. They used to call me “Father Rhythm” and “Father Temp” at St. John’s University in Minnesota. Over the years I sponsored eight international symposia on NFP, still misunderstood as the “old rhythm” method so often today. 

Indeed, there is a unique, rhythmic pattern of fertility and infertility in the human female. The old Calendar Rhythm was as effective as a means of birth control as the sinful condom and diaphragm of that time, provided the couple understood the reproductive system and the means of calculation, and didn’t cheat. In 42 years of priesthood, whenever couples told me NFP failed them, if they were frank and honest, I could prove to them in 99% of the cases that they never really understood or followed the method/lifestyle. 

Let me give you a short history of NFP and a brief description of the four major methods. In 1923 a famous Japanese gynecological surgeon, Dr. H. Ogino--after operating on thousands of women, studying their ovaries and knowing which day of the menstrual cycle his patient was on--wrote up his findings in a classic scientific report for a Japanese medical journal. The conclusions of this consummate scientist have never been contradicted. 

Ogino found that women ovulate between the 12th and 16th day before the onset of the next menstrual period. If a woman kept a history of her cycles over a year or two, she could, by applying a certain formula to the longest and shortest cycles, calculate the fertile portion of her next cycle. 

This was the old rhythm method, also known as Calendar Rhythm, so often unjustly maligned. Today it’s the Model T of NFP, scorned as “Vatican roulette” by ignorant cynics. Incidentally, Dr. Herman Knaus, a research minded Austrian gynecologist working in Prague in 1929 discovered more or less the same formula as Ogino, without any collusion between the two. 

The great disadvantage of the Ogino--Knaus method was the amount of sexual abstinence required in the case of severe cycle irregularity, especially at the premenopausal time, for many women. The greatest authority on the menstrual cycle, Prof. A.E. Treloar, has shown that the only thing regular about the female cycle is its irregularity. The notion of the 28-day cycle is only a statistical average. 

For quite some time it was known that when a woman ovulates, the hormone progesterone is fed into her system; this raises her temperature four- to six-tenths of a degree. Because there’s only one egg per cycle (usually), which can live no longer than 24 hours and often much less, a three-day temperature rise indicates that the egg is dead; from then on the female is infertile until menstruation. This came to be known as temperature rhythm. 

Because of varying cycle lengths and inability to predict ovulation, if marital relations took place too late in the first half of the cycle, ovum and sperm might meet, and a pregnancy might ensue. By applying the old Ogino-Knaus calculation to the first part of the cycle, this could be remedied. 

The late, great Jewish gynecological genius, Dr. Rudi Vollman, from whom I learned so much, proved that making this calculation, plus observing basal body temperature, led to very few pregnancies among 600 women whom he studied during World War II in Switzerland (to which he escaped from Hitler). The results of this classic study have never been challenged. 

The great physicist Sir Isaac Newton once remarked that every scientist stands on the shoulders of his forebears. This is true in the area of NFP. It was well known for a long time that the cervical mucus played an essential part in achieving pregnancy. Unlocking the mysteries of this mucus was the great contribution of Drs. John and Lyn Billings of Australia. 

They proved that by observing the qualitative changes of the mucus, married couples could predict the onset of their fertile time. By combining cervical mucus indications with temperature rise, couples have as effective a means of birth control as there is, short of sinful sterilization. This has been scientifically proven.

There are those who are persuaded that all that’s necessary in order to practice NFP is to monitor the cervical mucus; this is known as the Ovulation, Billings or Mucus Method. Others say some women cannot rely on mucus observation alone. In any event, adding a temperature indication and other signs too detailed to discuss here provides what’s known as the “Sympto-Thermal Method.” 

The greatest living authority on NFP, Dr. Joseph Roetzer of Austria, has had a fantastic success rate over the years with many clients in German-speaking countries. Dr. Thomas Hilgers of the Pope Paul VI Institute says that NFP, when properly understood and practiced, is over 95% effective, more so even than the “pill.” The largest NFP organization in the world, and one of the most effective, is the Couple to Couple League (P.O. Box 111184, Cincinnati, Ohio 45211 USA), founded by the persistent John Kippley in 1971. He says his group has trained so many teachers that if the U.S. bishops required NFP training before marriage, it could be given to virtually all engaged couples. 

Throughout history, the Catholic Church has been completely consistent about NFP. For example, St. Augustine (354-430 A.D.) showed in his writings that he was somewhat aware of rhythmic periods of fertility and infertility in the menstrual cycle, although the female ovum wasn’t discovered until 1829. 

In his monumental encyclical Casti Canubii (1930), Pope Pius XI roundly reasserted 20 centuries of Christian teaching on birth control, against the Anglican’s Lambeth Conference that same year, which embraced artificial birth control. The Pontiff recommended NFP for troubled couples. In 1951, Pope Pius XII gave two powerful talks to Catholic doctors begging for NFP research and teaching. 

Pope John Paul II has written on, preached, and promoted NFP more than all his predecessors combined--and he speaks and writes from much practical teaching experience.  [Note: this article was written before the death of John Paul II.]  As the Cardinal Archbishop of Krakow, he asked his priests never to witness the marriage of young couples that hadn’t learned God’s built-in way of controlling their fertility, should that be necessary for good reasons. (HLI supplied him with NFP information.) 

Being a practical man, he set up a multi-session marriage course, the themes of which were true marital love, the evil of contraception/sterilization/abortion, the theology of the body, the gift of children, and the goodness of NFP. (Long before the Second Vatican Council, Poland’s bishops had learned from bitter experience that contraception only led to abortion. Strangely, at the Council, they never got this message to the floor!) 

Taking this pre-marriage course was a requirement; versions of it soon spread throughout Poland. That the pleadings of Popes Pius XI, Pius XII, Paul VI and the strong recommendations of Pope John Paul II haven’t been followed by so many of our bishops is a tragedy in the extreme, considering the worldwide contraception/ sterilization/abortion/fornication/VD/AIDS mess and the seemingly terminal condition of the West and the Church there. 

Modern NFP is a reasonable and effective means of birth regulation; is very beneficial to physical, psychological and moral/spiritual health; and has none of the drawbacks of contraception. Any priest who has worked seriously with NFP knows that it produces great couples with good marriages. What’s more, these couples also are inherently pro-life because they value their fertility and revere God’s plan. 

Surely one of the main reasons NFP is not taught and promoted is plain ignorance. I was a priest for many years before I met a priest who understood enough about the human reproductive cycle that he could understand NFP. So many people have an inadequate grasp of the unique human reproductive system, causing many to fall for the myth that “rhythm” doesn’t work. 

This, I’m convinced, also explains why many don’t accept Humanae Vitae. They simply think there’s no way of controlling fertility except contraception. They have no idea that women are infertile most of the time, that the human female is one of the most infertile of all mammalian creatures. Animals copulate; human persons should relate and have ongoing, loving, ordered intercourse (in the context of Christian marriage). 

Obviously, God meant marital sexual intercourse to have the dual purposes of promoting unity (love) and procreation, i.e., being always open to life. When procreation isn’t advisable, the limited abstinence (eight to nine days) becomes the couple’s mutual expression of love. Or do you prefer Martin Luther’s view, “The purpose of marriage is not to have pleasure and be idle but procreate and bring up children, to support a household...”? 

Not one of the seven Catholic medical schools in the USA and Canada teaches NFP, leaving most doctors ignorant and antagonistic. And it’s a rare Catholic theologian who’s knowledgeable and interested. The seminary professors whom I lived with for years at St. John’s Abbey surely didn’t know NFP. 

Not many U.S. seminaries today have an acceptable treatment of NFP, even though Pope John Paul II, in section 33 of Familiaris Consortio, said “all young adults before marriage” should understand the unique human reproductive system. Today, priests are still being ordained without this pastorally indispensable information. Indeed, most leave the seminary thinking that dissenters such as Fr. Charles Curran are right and the Church is wrong, despite mountainous evidence to the contrary. 

It’s now evident to the careful observer that contraception, as Pope Paul VI so eloquently laid out in Humanae Vitae, leads to all kinds of evils, including abortion. This is known best to the abortion-pushers themselves. 

For example, Dr. Malcolm Potts, the famous international contraception promoter, says, “As people turn to contraception, there will be a rise, not a fall, in the abortion rate.” Again, English abortionist Dr. Judith Bury has observed, “There is overwhelming evidence that, contrary to what you might expect, the availability of contraception leads to an increase in the abortion rate.” I could repeat similar statements a hundred times from contraception advocates. 

Those who’ve studied the history of the population control industry know that decades ago, these evil people knew that contraception would never be enough, and that sterilization and abortion were absolutely necessary. (Where were we Christians?) Today, the proof is Brazil, where some 30% of all women of fertile age have been sterilized and at least 1.5 million babies are aborted illegally each year. The deadly combination of sterilization and abortion is propagated all over the world today, with immense funds. 

These are the reasons why, after 70 years of life and 42 years of priesthood, I’m thoroughly convinced that not much will change for the family. Nor will we rescue the family from today’s sex mess until we teach the essential virtue of chastity once more, and build effective, mandatory pre-marriage courses that teach Humanae Vitae and also Familiaris Consortio, the blueprint of family life education and promotion. 

But you cannot teach loving chastity in isolation. That’s why we need a complete revamp of catechetical instruction so it will include the virtues—-especially the virtue of chastity, which controls the powerful sexual impulse, and which, if not controlled, gives us the kind of world we are living in today. Of course, without spiritual formation, virtue is impossible. 

I, for one, cannot excuse parents who don’t expose their children to NFP.  The best chastity course and marriage preparation course is the intelligent loving example of parents who live a beautifully chaste and fruitful love. 

Fr. Paul Marx is the founder of Human Life International.