Over 30 years ago the founders of the Christian Family Movement (CFM), a worldwide Catholic family action group, conducted a survey to investigate the marital effects of practicing “rhythm.” Their final report indicated that many participants felt that periodic abstinence was harmful to their marriage and caused spiritual and religious distress. The CFM survey results were thought to have been influential in convincing the 1966 Papal Birth Control Commission to recommend a change in church teaching. The purpose of this paper is to report a re-analysis of the 1966 archived data (in the light of the Papal Encyclical Humane Vitae–On the Regulation of Birth) and to compare that study with responses from married couples using modern methods of NFP, i.e., methods that purport to be more effective and to have fewer days of periodic abstinence. This paper will provide an examination of the original study within its historical context and report on the responses relating to spirituality from the 1966 couples in comparison with couples currently practicing periodic abstinence through the Billings Ovulation Method.