On 1 July 1976, the US Supreme Court decided in the case Planned Parenthood v. Danforth that provisions of a Missouri law regulating abortion care were unconstitutional. That law, House Bill 1211, restricted abortion care by requiring written consent for each abortion procedure from the pregnant woman as written consent of the woman’s husband if she was married, or the written consent of her parents if she was unmarried and younger than eighteen. House Bill 1211 also required that physicians make efforts to preserve the lives of aborted fetuses. Following the passage of House Bill 1211 in 1974, two physicians and Planned Parenthood of Central Missouri challenged the law. Following the decisions by several lower courts, the US Supreme Court ruled on the case. The US Supreme Court struck down parts of a law that violated the US Constitution and the prior court case Roe v. Wade, and in doing so, they expanded access to abortion care in the US.

David Hunter Hubel studied the development of the visual system and how the brain processes visual information in the US during the twentieth century. He performed multiple experiments with kittens in which he sewed kitten’s eyes shut for varying periods of time and monitored their vision after reopening them. Hubel, along with colleague Torsten Wiesel, received the 1981 Nobel Prize in Physiology or Medicine for that research. By using kittens as models for human children and sewn eyes as models for congenital vision disorders, Hubel’s research demonstrated how vision impairments can affect the development of the visual system in humans. Furthermore, Hubel’s research has informed surgeons about the importance of operating on infants with vision impairments during the first months of life to prevent deterioration of the visual cortex of the brain and permanent vision loss.

During 1964, David Hubel and Torsten Wiesel studied the short and long term effects of depriving kittens of vision in one eye. In their experiments, Wiesel and Hubel used kittens as models for human children. Hubel and Wiesel researched whether the impairment of vision in one eye could be repaired or not and whether such impairments would impact vision later on in life. The researchers sewed one eye of a kitten shut for varying periods of time. They found that when vision impairments occurred to the kittens right after birth, their vision was significantly affected later on in life, as the cells that were responsible for processing visual information redistributed to favor the unimpaired eye. Hubel and Wiesel worked together for over twenty years and received the 1981 Nobel Prize for Physiology or Medicine for their research on the critical period for mammalian visual system development. Hubel and Wiesel’s experiments with kittens showed that there is a critical period during which the visual system develops in mammals, and it also showed that any impairment of that system during that time will affect the lifelong vision of a mammal.

Between 1953 and 1957, before the Meselson-Stahl experiment verified semi-conservative replication of DNA, scientists debated how DNA replicated. In 1953, James Watson and Francis Crick proposed that DNA was composed of two helical strands that wound together in a coil. Their model suggested a replication mechanism, later termed semi-conservative replication, in which parental DNA strands separated and served as templates for the replication of new daughter strands. Many scientists, beginning with Max Delbrück, questioned Watson and Cricks’ model and suggested new theories for DNA replication. By 1957, three theories about DNA replication prevailed: semi-conservative, conservative, and dispersive replication. Then, Matthew Meselson and Franklin Stahl conducted the Meselson-Stahl experiment, which returned results that supported the semi-conservative theory of DNA replication. The collaboration among scientists that ultimately produced concrete evidence of the DNA replication mechanism furthered both theoretical and physical explanations of genetics and molecular biology, providing insight into how life develops, reproduces, and evolves.

In 1963, Ignacio Ponseti and Eugene Smoley experimentally determined an effective and minimally invasive method of treating congenital clubfoot. Congenital clubfoot is a disorder in which a newborn’s foot is rigidly turned inwards and upwards. During the early 1960s, orthopedists often relied on invasive surgical procedures to treat clubfoot. In Ponseti and Smoley’s experiment, Ponseti and Smoley had a team of physicians treat patients with clubfoot using the Ponseti method, which consisted of manually manipulating each patient’s foot into a more desirable position and subsequently casting each foot to heal in place. After following up with the patients for several years, Ponseti and Smoley concluded that the Ponseti method is an effective alternative to the more invasive surgical procedures that orthopedists had often relied on. Ponseti and Smoley provided physicians with a novel and minimally invasive method of correcting foot deformities to ensure that developing infants maintain healthy feet.

Norbert Freinkel’s lecture Of Pregnancy and Progeny was published by the American Diabetes Association’s journal Diabetes in December of 1980. In the lecture, Freinkel argued that pregnancy changes the way that the female body breaks down and uses food. Through experiments that involved pregnant women as well as infants, Freinkel established the body’s maternal metabolism and how it affects both the mother and the infant. Freinkel’s main focus of research in the latter part of his life was diabetes, specifically in pregnant women. Diabetes occurs in around one to three percent of all pregnancies, which is 30,000 to 90,000 women a year in the US. Freinkel’s article indicates that pregnancy influences the metabolism in all pregnant females and that pregnancy complicated by diabetes is only an exaggeration of what occurs in all pregnant women. Subsequently, many doctors more closely monitored pregnant women and their blood sugar and insulin levels, as doctors were informed that all pregnant women have the capacity to become diabetic.

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.

In the 2016 case Whole Woman's Health v. Hellerstedt, the US Supreme Court ruled unconstitutional the Texas requirements that abortion providers have admitting privileges at local hospitals and that abortion facilities meet ambulatory surgical center standards. Whole Woman’s Health represented abortion care providers in Texas and brought the case against the commissioner for the Texas Department of State Health Services, John Hellerstedt. In a five to three decision, the US Supreme Court ruled that the requirements of the challenged law, Texas House Bill 2, had forced the majority of abortion care facilities to close. With fewer available facilities, women faced undue burdens of travel time and cost when seeking abortions, restricting their access abortion care. In previous US Supreme Court cases Roe v. Wade (1973) and Planned Parenthood v. Casey (1992), the Court ruled that placing undue burdens on women seeking abortion care was unconstitutional. Upholding those decisions in Whole Woman's Health v. Hellerstedt, the US Supreme Court struck down Texas House Bill 2 and protected women’s access to abortion care.

Between 1958 and 1962, physicians Olive W. Smith, George V. Smith, and Robert W. Kistner performed experiments that demonstrated the effects of the drugs MER-25 and clomiphene citrate on the female human body. MER-25 and clomiphene citrate are drugs that affect estrogen production in women. At the time of the experiment, researchers did not know which organ or organs the drugs affected, the ovaries and/or the anterior pituitary gland. To determine that, the physicians reviewed nine of their own previous studies in women in which they measured the urinary output of hormones after the administration of either drug. Based on their examination the researchers concluded that MER-25 appeared to influence the anterior pituitary gland in the brain to produce a response in the ovaries and that clomiphene citrate appeared to act on the ovaries. Their results provided early evidence about the mechanisms of both drugs. Later, clomiphene citrate became a common fertility drug.

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.