This book teaches about the billing method in family planning,it is recognized in medical history as one of the greatest discoveries of the twentieth century.Millions around the world has used it to identify natural signs of fertility and infertility,or avoid pregnancy,as well as use to monitor their reproductive health.This book teaches about the billing method in family planning,it is recognized in medical history as one of the greatest discoveries of the twentieth century.Millions around the world has used it to identify natural signs of fertility and infertility,or avoid pregnancy,as well as use to monitor their reproductive health.This book teaches about the billing method in family planning,it is recognized in medical history as one of the greatest discoveries of the twentieth century.Millions around the world has used it to identify natural signs of fertility and infertility,or avoid pregnancy,as well as use to monitor their reproductive health.This book teaches about the billing method in family planning,it is recognized in medical history as one of the greatest discoveries of the twentieth century.Millions around the world has used it to identify natural signs of fertility and infertility,or avoid pregnancy,as well as use to monitor their reproductive health.