As the Sixties unfolded with more and more attention being given to the birth control Pill, Dr. G. K. Doering saw the need to test the effectiveness of the Calendar-Temperature system. In his first system, he predicted that post ovulation infertility started by the evening of the SECOND day of sustained thermal shift. I do not know what effectiveness he found, but he was surprised at the number of surprise pregnancies. He changed his post-ovulation infertility rule by adding one more day. The post-ovulation infertile phase was thus predicted to start on the evening of the THIRD day of sustained thermal shift.
In third-day study, he analyzed two groups. One group abstained from the marriage act from the beginning of menstruation until the evening of the third day of elevated temperatures. In this group, he found a pregnancy-avoidance effectiveness of 99.2%.
The other group considered the early part of the cycle as infertile, using a calculation based on the thermal shift pattern in previous cycles. In this group, he found a pregnancy avoidance effectiveness of 96.9 percent. In both groups he included pregnancies that are now called imperfect-use pregnancies. This included marriage acts during the fertile time and even at least one pregnancy from a couple using his previous second-day rule. You can read the entire study at http://nfpandmore.org/Doering-1967-100315.pdf. This is the only English language translation of which we are aware; we hired a Professor of German to do it for us.
The IRONY. This study was published in a German medical journal on June 9, 1967. That’s 13 months and two weeks before the publication of Humanae Vitae. At this time, Pope Paul VI was struggling with the birth control issue. Seeing this research would have given him great encouragement about the current level of effectiveness of this natural system of avoiding pregnancy. But did he ever see it? I have to wonder. With hindsight we know that the German bishops at that time as a whole did not accept the Traditional Catholic teaching against the use of unnatural forms of birth control. That seems to be the case also today. Germany is home of one of the original researchers regarding natural family planning, home of the Catholic priest who invented the Calendar-Temperature form of NFP, home of Dr. G. K. Doering who developed a highly effective Temperature-only system, and also home to the bishops who were highly non-supportive of Humanae Vitae.
As Jesus experienced his agony in the garden of Gethsemane, Peter, James and John kept falling asleep. As the Church today is experiencing its agony of sexual sins, too many bishops seem to be proving themselves to be the descendants of the Apostles, asleep at the hour of need. Dear reader, please pray for our bishops that they will wake up and realize what great helps the Lord has given his people to live out the teaching of Humanae Vitae.
Tomorrow: The Covenant Theology
John F. Kippley
Sex and the Marriage Covenant