Rock, John Charles, 1890-

John C. Rock (1890-1984) was the founder of the Rock Reproductive Study Center at the Free Hospital for Women in Brookline, Massachusetts, and Clinical Professor of Gynecology at Harvard Medical School. Rock collaborated with colleague Gregory Pincus and Pincus's assistant Min-Chueh Chang, during the 1950s in the clinical trials and development of oral contraceptives, commonly known as the birth control pill. Rock is also credited with colleague Arthur Hertig and laboratory assistant Miriam F. Menkin for completing the earliest human in vitro fertilization experiments in the United States in 1944. As a fertility specialist, gynecologist, and medical educator, Rock, a Roman Catholic, gained notoriety for advocating the usage of birth control despite his religious beliefs. His research areas included fertility, early stages of contraception, human embryo development, in vitro fertilization, the freezing and preservation of sperm cells, and clinical disorders of human reproductive physiology.

John Charles Rock was born on March 24, 1890 in Marlborough, Massachusetts. He received an S.B. from Harvard College in 1915, and his MD from Harvard Medical School in 1918. Rock began his residency in obstetrics at the Boston Lying-In Hospital in 1919. He held several academic appointments at Harvard Medical School between 1922 and his retirement from the Harvard Medical School faculty in 1956, culminating in his appointment as Clinical Professor of Gynecology. Rock taught clinical obstetrics for over 30 years at Harvard Medical School.

Rock was initially trained as a surgeon whose early medical career focused on infertility. As a medical educator at Harvard Medical School in Boston, Massachusetts, a state which at the time had legally banned the distribution of contraceptives, Rock covertly taught students the advantages of these methods. In 1931, Rock signed The Doctors’ Bill to Clarify the Law, a petition signed with other 15 physicians endorsing birth control and permitting doctors to prescribe, and chartered hospitals to dispense contraceptive devices.

From 1926 to 1956, Rock was the director of the Fertility and Endocrine Clinic at the Free Hospital for Women, one of the first centers of its kind in the United States. Rock created the Rhythm Clinic at the Free Hospital for Women in 1936 as a facility to educate women of the timing of their menstrual cycles to increase their chances of conception. Rock and Hertig collaborated, with Menkin’s assistance, to determine the time sequence of fertilization, ovum transport, and implantation. Their research, funded by the Carnegie Institute of Washington, led to Rock and Hertig's being the first researchers to attempt the fertilization of human ovum in vitro in 1944; and their recovery of human embryos from two to seventeen days after fertilization.

Upon his retirement from Harvard Medical School and the active staff of the Free Hospital for Women in 1956, Rock founded the independent Rock Reproductive Study Center, later known as the Rock Reproductive Clinic, Inc., in Brookline, Massachusetts. At this facility, Rock’s research focused on fertility and sterility and the development of oral contraceptives, commonly known as the birth control pill. In the early 1950s, Rock partnered with Gregory Pincus, and his assistant Min-Chueh Chang, to develop a progestin-based oral contraceptive that could halt ovulation in females. Their research was largely funded by Katherine Dexter McCormick, heiress to the McCormick reaper fortune, and was ardently supported by birth control pioneer Margaret Sanger. Pincus and Chang demonstrated the effectiveness of progestins as an ovulation inhibitor in their experiments in rabbits and rats in their research at the Worcester Foundation for Experimental Biology. Following their positive results, in 1954, Rock successfully tested oral progestins to prevent ovulation in a select group of 27 of his infertility patients. Rock instructed his patients to start taking the progesterone pills five days after the start of their menstrual periods. For the next three months, the women took the pills for twenty consecutive days, and then resumed taking the oral progesterone the fifth day after their next period. Within four months of taking the pill, four of the women were pregnant, indicating a fertility rebound, commonly known as the Rock Rebound, after taking the pill; the results also revealed oral progesterone could halt ovulation, thus preventing pregnancy.

With the success of the progestins in both studies, a controlled field trial of the newly-developed oral contraceptive was then completed in San Juan, Puerto Rico in 1956, with the assistance of colleague Celso-Ramon García and Edris Rice-Wray, Medical Director of the Puerto Rico Family Planning Association and Director of the United States Public Health Field Training Center. The Puerto Rico field trial was a success for Pincus and Rock, with 265 women participating in the trial by taking the pill for 20 days for six months. Subsequent pregnancies occurred in 85 percent of the women who stopped taking the pill in order to get pregnant. The Food and Drug Administration (FDA) approved the newly-developed progesterone pill as a treatment for menstrual disorders in 1957 on the basis of the Puerto Rico field trial results. After further trials, including a second trial in Puerto Rico, the FDA approved Enovid, developed by Searle Pharmaceuticals as the first birth control pill, for contraceptive use in 1960.

Rock garnered extensive publicity for his role in the development of the birth control pill. Much of the attention was centered on Rock's Catholic beliefs, and his willingness to support the pill despite his faith's opposition. In 1963, Rock published The Time Has Come: A Catholic Doctor’s Proposals to End the Battle Over Birth Control, a book which advocated for the widespread acceptance of the birth control pill as a legitimate contraceptive device, and was a direct challenge to the Catholic Church's traditional stand against contraceptives. After publishing his book, Rock lectured extensively in the United States, Europe, South America, and Asia, defending the pill as a means of natural contraception and warning audiences of the dangers of global overpopulation. The Catholic Church remained adamant in its opposition to the birth control pill, and Rock's research. In 1968, Pope Paul VI issued an encyclical, Humanae Vitae, renewing the Church's prohibition of artificial forms of birth control, including the pill.

Rock maintained his Reproductive Clinic through the late 1960s, affiliated with Harvard Medical School until 1967. He sold his practice in 1969 to Dr. John H. Derry of Newton, Massachusetts, who established the Derry-Rock Clinic in Roxbury, Massachusetts. Rock remained at the clinic performing research activities until 1971 when at age 80, he retired to Temple, New Hampshire.

John C. Rock died after a brief illness in 1984. He was 94 years old.

From the guide to the Personal and Professional Papers, 1918-1983, (Francis A. Countway Library of Medicine. Center for the History of Medicine.)