Dr. John Billings
In 1953, he began work on a method of natural family planning, involving observation of several indicators of fertility and infertility, gradually focusing on the changes to cervical mucus patterns of sensation. His wife, Evelyn, became involved from 1963. The couple founded the World Organisation of the Ovulation Method Billings (WOOMB) as the body responsible for teaching the method throughout the world. Although Billings maintained his career as a consulting neurologist to St Vincent's Hospital, he and his wife spent a large part of each year traveling to other countries, and training teachers in the Billings Ovulation Method, lecturing to doctors and students, and establishing teaching centers. The Method pioneered by the Billings was approved by both the Catholic Church and used by the World Health Organization. It was the only natural method accepted by the Chinese Government.