Edward Charles Dodds researched the function and effects of natural and artificial hormones on the endocrine system in England during the twentieth century. Though he first worked with hormones such as insulin, Dodds focused on the effects of estrogen in the body and how to replicate those effects with artificial substances. In 1938, along with chemist Robert Robinson, Dodds synthesized the first synthetic estrogen called diethylstilbestrol. Despite the wide use of diethylstilbestrol to treat a variety of hormonal problems like miscarriages during pregnancy and menopause, Dodds argued against the use of synthetic substances in the human body due to their unknown effects. Just before Dodds's death, his hypotheses were confirmed when researchers showed that people exposed to diethylstilbestrol often developed cancer. Dodds was one of the first researchers to investigate the endocrine or hormone system in humans, and his research led to the creation of other synthetic hormones used in contraceptive pills and hormone replacements.

In 1948, Olive Watkins Smith published 'Diethylstilbestrol in the Prevention and Treatment of Complications of Pregnancy' in the American Journal of Obstetrics and Gynecology. In 632 women treated with diethylstilbestrol, Smith demonstrated that the drug stimulated the production of progesterone, a hormone that regulates the uterine condition during pregnancy. On the basis of her article, and several follow up articles authored by Smith and her husband, George Van Siclen Smith, physicians around the world began prescribing DES to women at risk for pregnancy complications like miscarriage and premature delivery. However, in 1953, researchers at found that DES did not prevent pregnancy complications. In 1970, researchers linked fetal exposure to DES to rare and severe cancers later in life. Researchers labeled DES as an endocrine disruptor, a substance that disrupts the hormone system of the body across multiple generations.

In the legal case In re Agent Orange Product Liability Litigation of the early 1980s, US military veterans of the Vietnam War sued the US chemical companies that had produced the herbicide Agent Orange, and those companies settled with US veterans out of court. Agent Orange contains dioxin, a chemical later shown to disrupt the hormone system of the body and to cause cancer. As veterans returned to the US from Vietnam, scientists further confirmed that exposure to Agent Orange caused a variety of cancers in veterans and developmental problems in the veterans' children. The veterans and their families held the chemical manufactures of Agent Orange liable for their injuries and the injuries to their children. The chemical companies settled the case out of court in 1984 for $180 million, to be used for medical expenses or compensation for death relating to veterans' exposure to Agent Orange. Agent Orange's use in the Vietnam War affected close to ten million people in the US, including members of the US military directly exposed to it, and their children conceived years after direct exposure.

William Withey Gull studied paraplegia, anorexia, and hormones as a physician in England during the nineteenth century. In addition to caring for patients, he described the role of the posterior column of the spinal cord in paraplegia, and he was among the first to describe the conditions of anorexia and of hypochondria. He also researched the effects of thyroid hormone deficiencies in women who had malfunctioning thyroid glands. Gull's research on thyroid hormone confirmed that chemicals in the body directly affect health, and he contributed to the foundation of endocrinology, the scientific field for the study of hormones.

In its 1993 decision Daubert v. Merrell Dow Pharmaceuticals, Inc., the US Supreme Court established the Daubert Standard for evaluating the admissibility of scientific knowledge as evidence in US federal courts. When it began in trial court, the case addressed whether or not Bendectin, an anti-nausea medication taken during pregnancy, caused birth defects. However, after the trial court dismissed the case for lack of admissible evidence, Daubert v. Merrell Dow Pharmaceuticals, Inc. advanced through appeals courts to the US Supreme Court, where the Justices defined the criteria by which scientific knowledge, which for them included a least theories based on evidence, expert testimony from scientists, and scientific techniques, could be introduced and used in court cases as evidence. The Daubert Standard states that the judge of a case is responsible for determining what claims are admissible as scientific knowledge and as evidence in the case. The admissibility should be determined by the falsifiability of the claims, by whether or not they had passed peer reviewed, by the general scientific acceptance of the claims, and for techniques, by their error rates of the techniques. Daubert v. Merrell Dow Pharmaceuticals, Inc. set a landmark precedent in the US judicial system and influenced most subsequent legal cases that appealed to science to establish facts in trials.