Charles Knowlton was a physician and author who advocated for increased access to information about reproduction in the nineteenth century in the US. Throughout his early medical education, Knowlton was particularly interested in anatomy and on several instances robbed graves for bodies to dissect. In 1832, Knowlton authored The Fruits of Philosophy, a pamphlet that contained detailed descriptions of the reproductive organs and information on conception and methods to control reproduction. Knowlton circulated his work among his patients until it was republished in Boston, Massachusetts, in 1832. For publishing a book on sex and methods of birth control, Knowlton was convicted of breaking obscenity laws, which prevented the transmission of obscene materials. After his death, social activists Charles Bradlaugh and Annie Besant republished his work in London, England. Knowlton’s writing about sex and birth control allowed individuals to understand and take control of their reproduction and initiated a public discussion about obscenity laws.

In the late-twentieth century in the United States, Catherine DeAngelis was a pediatric physician, researcher, and editor of multiple medical journals. During her time with the Journal of the American Medical Association, DeAngelis became the journal’s first female editor. At Johns Hopkins University in Baltimore, Maryland, she studied how physician-nurse interactions affected patient care, how immunizations and adolescent pregnancy affected children, and how medications affected men and women differently. She also worked to reduce gender inequality in the practice of medicine by publishing articles that addressed the pay gap between men and women at Johns Hopkins. Throughout her career, DeAngelis advocated for equality between men and women in the medical field and supported equal treatment of women as patients and as practitioners of medicine. By doing so, she helped women become more central participants in medicine and therefore helped increase the focus on women's health in medicine.

David Baltimore studied viruses and the immune system in the US during the twentieth century. In 1975, Baltimore was awarded the Nobel Prize in Physiology or Medicine for discovering reverse transcriptase, the enzyme used to transfer information from RNA to DNA. The discovery of reverse transcriptase contradicted the central dogma of biology at the time, which stated that the transfer of information was unidirectional from DNA, RNA, to protein. Baltimore’s research on reverse transcriptase led to the discovery of retroviruses, which accelerated the development of treatments for human immunodeficiency virus or HIV and cancer vaccines. Baltimore also influenced public policy and opinion on genetic engineering. In 1975, he helped organize the Asilomar Conference in Pacific Grove, California, which discussed the regulation of recombinant DNA or the DNA created using multiple sources of genetic material. Baltimore’s research demonstrated how retroviruses replicate and infect cells, and his influence on the Asilomar Conference on Recombinant DNA has guided discussions about regulating biotechnology.

Twentieth-century researcher Ernest John Christopher Polge studied the reproductive processes of livestock and determined a method to successfully freeze, thaw, and utilize viable sperm cells to produce offspring in animals. In 1949, Polge identified glycerol as a cryoprotectant, or a medium that enables cells to freeze without damaging their cellular components or functions. Several years later, Polge used glycerol in a freezing process called vitrification, which enabled him to freeze poultry sperm, thaw that sperm, and use it to fertilize vertebrate embryos. He later adapted those methods to be applied to several other species including goats, cows, and pigs, which enabled farmers to fertilize livestock with sperm or embryos after long-term storage. Additionally, Polge's development of methods to freeze and store living samples has equipped reproductive health researchers and medical professionals with the abilities to mass collect and store human sperm.

During the twentieth century in the United States, Bernadine Patricia Healy was a cardiologist who served as the first female director of the National Institutes of Health or NIH and the president of both the American Heart Association and the American Red Cross. Healy conducted research on the different manifestations of heart attacks in women compared to men. At the time, many physicians underdiagnosed and mistreated coronary heart disease in women. Healy's research illustrated how coronary heart disease affected women. Healy was also the deputy science advisor to the United States president Ronald Reagan, and during her time at the NIH, she founded the Women's Health Initiative. That initiative was a $625 million research study that aimed to determine how hormones affected diseases specific to postmenopausal women. Through her research and leadership positions, Healy helped improve women's healthcare in the US and helped expand the resources available for research into women's health.

Ephraim McDowell was an US abdominal surgeon who in 1809 performed one of the first successful ovarian surgeries. McDowell conducted his medical practice in Danville, Kentucky, where he used novel methods of ovariotomy to remove a twenty-two and a half pound ovarian tumor from his patient, Jane Crawford. At the time, surgeons performed ovariotomies by making an incision into each patient’s ovary to remove a mass. However, their patients often died from infection or blood loss. McDowell’s methods included making an incision into the abdominal muscles, draining the abdomen of blood, and using adhesives with sutures to close the wound. McDowell performed one of the first invasive abdominal surgeries in which the patient survived, and his surgical techniques established the potential safety and efficacy of ovarian and abdominal surgery in the 1800s.

Annie Dodge Wauneka, a member of the Navajo Tribal Council in Window Rock, Arizona, from 1951 to 1978, advocated for improved lifestyle, disease prevention, and access to medical knowledge in the Navajo Indian Reservation, later renamed the Navajo Nation. Wauneka served as chair of the Health and Welfare Committee of the Navajo Tribal Council and as a member of the US Surgeon General’s Advisory Committee on Indian Health. Wauneka advocated for initiatives aimed at promoting education, preventing tuberculosis, and reducing the infant mortality rate. In 1963, she was awarded the Presidential Medal of Freedom. Wauneka’s initiatives to educate mothers about child health and increase hospital births reduced infant mortality rates in the Navajo Indian Reservation during the twentieth century.

Andreas Vesalius, also called Andries van Wesel, studied anatomy during the sixteenth century in Europe. Throughout his career, Vesalius thoroughly dissected numerous human cadavers, and took detailed notes and drawings of his research. Compiling his research, Vesalius published an anatomy work titled De humani corporis fabrica libri septem (On the fabric of the human body in seven books). The Fabrica included illustrations of dissected men, women, and uteruses with intact fetuses. Vesalius was one of the first physicians to accurately record and draw what was inside of the human body based on his findings from human autopsies, which led to improved understanding of the human body and enhanced surgery techniques.

In the nineteenth century, Elizabeth Blackwell was a women’s healthcare reformer and the first woman to receive her medical degree in the United States. She practiced medicine as a primary care physician in both the United States and the United Kingdom. Blackwell graduated medical school from Geneva Medical College in Geneva, New York, where she was the first woman to receive a medical degree in the US. Throughout her career, Blackwell focused on her patients’ rights to access healthcare and education pertaining to healthcare, particularly the rights of women and children, whom she treated in a hospital she cofounded. Blackwell influenced the medical care during the Civil War in the United States by training nurses to treat soldiers injured in battle. In her lifetime, Blackwell educated women on their health and careers as healthcare providers, and as the first woman to receive a medical degree, made it easier for other women to become physicians in the United States.

During the twentieth century, Norbert Freinkel studied hormones and diabetes in the US. Freinkel conducted many experiments that enabled him to determine the factors that influence hormones of the thyroid gland to bind to proteins and to determine the effects that those thyroid hormones have on surrounding tissues. Furthermore, Freinkel researched gestational diabetes, which is diabetes that occurs for the first time during a women’s pregnancy. That type of diabetes is caused by a change in the way a woman’s body responds to insulin, a hormone made in the body. Infants who are born from pregnant women with gestational diabetes can possess many different medical conditions such as type 2 diabetes, respiratory distress syndrome, and low blood sugar. Through his research on gestational diabetes, Freinkel found that all pregnant women go through metabolic changes, not just gestational diabetics.