Frequently, when one mentions natural family planning methods, the response is doubt, bewilderment, ridicule, or scorn. Much of this is due to the fact that many people know only of the rhythm method, which depends on a calculation based on the menstrual pattern. What many people do not know, including physicians and nurses, is that in Australia Drs. John and Lyn Billings have been scientifically researching natural methods of family planning for 25 years, and they have pioneered this Ovulation Method of family planning. The Billings Ovulation Method depends only on the mucus sign. It is based on a scientific knowledge of the combined fertility of husband and wife, and an understanding of the physiology of the female body through simple observations. Important facts relating to the practice of the method include: ovulation takes place only once in the cycle; mucus is secreted by the cervical mucosa before ovulation; the ovum lives for only 3 days at the most; and the sperms live for 5 days at the most, and only in the presence of this fertile mucus. There a 2 types of mucus. The 1st type to appear is cloudy or white. It is nonslippery, sticky, and breaks when stretched between 2 fingers. The 2nd type is like the part of a hen's egg. It is very slippery, much clearer than the former, and stretches when pulled between 2 fingers. This is fertile mucus, and ovulation occurs on the last day that this is present. Of course, it cannot be recognized as the last day until its absence is observed on the following day. The mucus sign can be both seen and felt. After a few months a woman will readily recognize her fertile time, but daily charting is advocated. Simple signs, representing the various observations, are taught. Once a couple knows and understands their combined fertility through the observation of the mucus sign they can plan their family. Rules of the method are outlined. The self control required by this method can only serve to increase the selfless love and unselfish care and respect between partners.