In 2002, the Writing Group for the Women's Health Initiative Investigators published the article Risks and Benefits of Estrogen Plus Progestin in Healthy, Postmenopausal Women: Principal Results from the Women's Health Initiative Randomized Controlled Trial in The Journal of the American Medical Association. In the article, the authors report on the Women's Health Initiative, which was a study initiated by the National Institutes of Health to determine the effects of hormone therapy in postmenopausal women, or women whose menstrual cycles have stopped, from the ages of fifty to seventy-nine. The researchers attempted to determine if a link existed between a common type of hormone therapy, a combination of estrogen and progestin, and prevalent diseases in postmenopausal women, including cardiovascular disease and cancer. As reported by the authors in their article, the researchers discontinued the study after five years when they found that there were many risks associated with the use of estrogen plus progestin hormone therapy, including increased risks of breast cancer and heart diseases.

In the early 1920s, researchers Edgar Allen and Edward Adelbert Doisy conducted an experiment that demonstrated that ovarian follicles, which produce eggs in mammals, also contain and produce what they called the primary ovarian hormone, later renamed estrogen. In their experiment, Doisy and Allen extracted estrogen from the ovarian follicles of hogs and proved that they had isolated estrogen by using a measurement later renamed the Allen-Doisy test. Allen and Doisy’s 1923 experiment to isolate estrogen showed it was made within the ovaries and also established a method for isolating the sex hormone. That method provided a basis for future research on hormones. Later researchers showed that estrogen functions in the menstrual cycles of primates by signaling for the tissue lining the uterus (endometrium) to thicken in preparation for possible implantation of a fertilized egg.

Hormone replacement therapy, or HRT, is a form of medication often used to treat the symptoms of menopause. According to the National Institute on Aging, menopause is the point in a female’s life twelve months after she has had her last period. The time leading up to menopause, often called perimenopause, is a transition stage when levels of sex hormones, namely estrogen and progesterone, begin to fall. For approximately eighty-five percent of menopausal females, that decline results in symptoms such as vaginal dryness, shifting moods, and hot flashes, or an abrupt feeling of warmth typically in the upper body. HRT replenishes a person’s sex hormones, and though there are many methods of HRT, people most commonly take a pill that contains either estrogen only or both estrogen and progesterone. HRT has evolved scientifically but has at times resulted in controversy over potential side effects. Despite historical controversy, as of 2024, researchers recognize that with careful consideration of an individual's health conditions and history, HRT can be an effective treatment for menopausal symptoms.

In 1938, physician Henry Hubert Turner published “A Syndrome of Infantilism, Congenital Webbed Neck, and Cubitus Valgus,” hereafter “A Syndrome of Infantilism,” in the journal Endocrinology, in which he described a condition that researchers later named Turner syndrome. Turner syndrome is a genetic condition that affects biological females, characterized by a partially or completely missing X chromosome. In the paper, Turner describes a previously unrecognized set of symptoms in seven different females, including a lack of physical and sexual development, infertility, webbed neck, and elbow deformities, among others. Turner also records various methods of hormone treatments for his patients, such as growth hormone and estrogen injections. “A Syndrome of Infantilism” was one of the first published descriptions of Turner syndrome, a developmental condition that affects one in 2,500 live female births globally, and highlighted the use of hormone treatments to promote the development of stunted physical and sexual growth.