Dr. Evelyn Billings, who helped develop a major method of natural fertility regulation, is being remembered after her recent death as a wonderful inspiration, said a doctor at the Natural Family Planning Center.

"That's how we feel about her, she was wonderful, she inspired us, but she didn't restrict us," Dr. Hanna Klaus told CNA from her D.C. office on Feb. 19.

"She and John, her husband, wanted us to do everything that was within our creativity to promote the method, but it was always for the good of families."

Billings died Feb. 16 at the age of 95 after a short illness. She was a pediatrician, and together with her husband Dr. John Billings, developed the Billings Ovulation Method of spacing births. Her work studying breastfeeding mothers and peri-menopausal women made a major contribution to the development of the method.

The Billings Method helps women identify their fertile state based on their menstrual cycle. Based on this knowledge of the fertile period, a couple can the try to either achieve or avoid a pregnancy without the use of artificial contraceptives that violate Catholic teaching.

The couple developed the method in 1953 after they had been asked to devise such a technique by the Catholic Marriage Guidance Bureau.

Evelyn Billings authored "The Billings Method" in 1980. It has been published in 22 languages and exposed natural family planning to millions of couples in some 120 countries.

She also travelled throughout the world promoting natural family planning, and a substantial drop in the abortion rate in China was attributed to her work and her husband's, after they trained thousands there how to teach their method of regulating fertility. The Billings Method is the only natural fertility method allowed by the government there.

Billings was made a Dame Commander of Saint Gregory the Great by John Paul II in 2003. She was an active member of the Pontifical Academy for Life and a member of the Order of Australia.

"She and John had this gift of relating to everyone and getting them excited about possessing the gift of fertility and sexuality and managing it in a very human way. They themselves were very happily married," Klaus said.

"They were just a wonderful team of physicians."

Klaus recounted how the Billings decided to adopt a child, Kathryn, after Evelyn saw her at a nursery.

"They were just wonderful, sweet, holy people," Klaus said, explaining that Billings was a warm, kind mother.

Billings is survived by eight of her nine children, as well as 39 grandchildren and 31 great grandchildren. She was preceded in death by her husband John in 2007.