CHICAGO -- Dr. Leo J. Latz, 91, a pioneer in natural family planning, died Monday at his home in Chicago's West Ridge neighborhood.
He published the booklet "The Rhythm," which introduced the fertility-cycle means of birth control to the American public in 1932.
He was a past chief of staff at Alexian Brothers and St. Elizabeth's Hospitals.
Dr. Latz originated the term "the rhythm method" for a form of birth control that eventually won the approval of the Roman Catholic Church. The system is based on the fact that women are fertile only five or six days in a 28-day menstrual cycle.
The Catholic Church was slow to accept the rhythm method, having long held that abstinence was the only acceptable method of birth control.
Cardinal George Mundelein, then archbishop of Chicago, approved the pamphlet but later withdrew his blessing.
The Jesuit magazine America denounced the book, and Dr. Latz was fired from the faculty of Loyola University Medical School, according to Catholic historian Ellen Skerritt.
Within two years, 60,000 copies of the booklet were in circulation. It has gone through 26 editions.
Dr. Latz, who had an extensive medical practice and counseled hundreds of thousands of married couples in the last 60 years, taught in the nursing schools of Mercy, St. Elizabeth's and Alexian Brothers Hospitals.
He was honored in 1977 as one of only five lay associate members of the Congregation of Alexian Brothers.
Survivors include his wife of 61 years, Margaret; a son, Leo Jr.; a daughter, Margaret Boyle; and three sisters.