None of these apps are the rhythm method. That being said, they are also not the time-proven methods approved of by 'religious organizations'. That is their dan

None of these apps are the rhythm method. That being said, they are also not the time-proven methods approved of by 'religious organizations'. That is their danger. The church dedicates a lot of time to educating couples in actually proven methods. Both the sympto-thermal method and the various mucus only methods (billings and creighton) have been demonstrated effective by large studies. Studies on the sympto-thermal method report a 99.4% efficacy rate, and similar for billings and creighton. source: https://academic.oup.com/humrep/article/22/5/131/2914315 https://academic.oup.com/humrep/article/22/5/131/2914315 The religious organizations you mention (like the couple to couple league, the largest provider of fertility awareness education in the united states) have never taught the rhythm method. The rhythm method was used before the 1950s, but we've had significantly better methods since then. In fact, the Billings method has -- in the pas at least -- been endorsed by the government of china as a way to enforce the one-child policy. The main failure from these apps is lack of education. Most people using them have never had a formal education in them, despite such things being available. My wife and I are glad at having taken an actual course, rather than learning from an app or book. Our experience has been perfectly acceptable