He was the founder of the Rock Reproductive Study Center at the Free Hospital for Women in Brookline, Massachusetts and a Clinical Professor of Gynecology at Harvard Medical School.
[3] He worked on plantations for the United Fruit Company in Guatemala and for an engineering firm in Rhode Island and realized that business was not his calling.
He became friends with the company's doctor, Neil MacPhail, who mentored Rock and allowed him to assist in surgeries at the hospital he managed.
[4] and founded his own medical practice a few years later[3] As his career progressed, and despite being a devout Catholic, Rock also became known for his acceptance of birth control.
In the 1930s, he founded a clinic to teach the rhythm method, the only birth control conditionally regarded as moral by the Catholic Church at the time.
[3] For most of Rock's medical career, he directed and practiced at the Fertility and Endocrine Clinic at the Free Hospital for Women in Boston, Massachusetts.
[2] In addition to practicing as a medical doctor, he was an active researcher, striving to discover new knowledge and offer more help to his female patients.
In collaboration with Marshall Bartlett, Rock conducted research on the schedule of ovulation and the sequential stages of the endometrium during a woman's menstrual cycle.
[2] Their study reported in 1944 that eggs fertilized outside the human body had successfully initiated embryonic cleavage for the first time in a lab setting.
[2] This research opened a door of possibilities for future technology to overcome obstacles in reproductive medicine, providing hope to many women experiencing infertility.
Although Rock and Menkin's findings were groundbreaking, the research for in vitro fertilization was not advanced and safe enough to be used in clinical practice until many decades later.
[2] Rock hired Miriam Menkin, a research technician who assisted Gregory Pincus in the rabbit IVF experiments.
In 1968, the papal encyclical Humanae vitae laid out definitively the Catholic Church's opposition to hormonal and all other artificial means of contraception.
[8] The initial clinical trials were codeveloped by Rock and were funded by Katherine McCormick, a collaborator of Sanger who dreamed of the creation of a female-controlled contraceptive method.
[10] Rock and Pincus wanted to give the body an opportunity for menstruation so that this drug would not conflict with the natural biological processes in women.
[10] Rock's written scientific research explained how this drug succeeded in inhibiting ovulation, but skepticism remained present among authorities.
[10] To provide further evidence of their developed oral contraceptive pill, Pincus and Rock moved their studies to Puerto Rico to conduct their trials on a larger scale in 1956.
[10] The pill was reported successful regarding preventative purposes but brought too many side effects for legal consideration, which was stated by the medical director of the clinical trials in Puerto Rico.
[10] This was an obstacle for the two doctors, but their further research and testing revealed the addition of estrogen in combination with progesterone can help reduce menstrual comfort.