Research Article "Natural family planning": effective birth control supported by the Catholic Church. British Medical Journal 1993; 307 doi: https://doi.org/10.1136/bmj.307.6906.723 (Published 18 September 1993) Cite this as: British Medical Journal 1993;307:723 Article Related content Metrics Responses Peer review Related articles Letter Natural family planning. Couples take chances. Published: 16 October 1993; British Medical Journal 307 doi:10.1136/bmj.307.6910.1003-a Letter Natural family planning. Effective only if used perfectly. Published: 16 October 1993; British Medical Journal 307 doi:10.1136/bmj.307.6910.1003 Letter Natural family planning. Abstinence unnatural in primates. Published: 16 October 1993; British Medical Journal 307 doi:10.1136/bmj.307.6910.1004-c Letter Natural family planning. Review's enthusiasm based on flawed evidence. Published: 16 October 1993; British Medical Journal 307 doi:10.1136/bmj.307.6910.1004-d