No. The old calendar rhythm method of the 1930’s is obsolete in the face of modern medical research. Unfortunately, the medical community and the general population have had limited opportunity to learn of these advances. Promotion of hormonal contraception by the pharmaceutical industry has overshadowed the field of family planning. Doctors in training receive practically no education in the field of modern natural family planning. To gain this knowledge, physicians must attend specialized medical education programs that are not yet widely available.