Mary Ware Dennett, an activist in the US for birth control and sex education in the early twentieth century, wrote an educational pamphlet in 1915 called “The Sex Side of Life, and it was published in 1919. The pamphlet defined the functions of the sex organs, emphasized the role of love and pleasure in sex, and described other sexual processes of the body not usually discussed openly. In the early twentieth century in the US, individuals did not have wide access to sex education due to the limitations enforced by the Comstock Act, which prohibited the distribution and discussion of topics that were considered obscene. In 1929, the US tried Dennett for mailing her pamphlet as a violation of the Comstock Act, sending obscene material through the United States Postal Service. Dennett’s pamphlet, Tthe “Sex Side of Life,” and her subsequent trial, United States v. Dennett, contributed to a national discussion about sex education and human reproduction and led to the revision of reproduction- related obscenity laws.

Hideyo Noguchi researched bacteria, including Treponema pallidum, the bacterium that causes syphilis, in Japan and the US during the early 1900s. Syphilis is a bacterial infection that spreads primarily through sexual transmission and can cause symptoms such as rashes, genital sores, and even organ damage. Noguchi recognized that Treponema pallidum causes neurosyphilis, which is when the syphilis infection spreads to the covering of the brain, the brain itself, or the spinal cord. Before Noguchi’s work, researchers knew about Treponema pallidum and the symptoms of the disease but did not know that untreated syphilis could lead to neurosyphilis. Additionally, Noguchi worked to alter and improve methods to diagnose syphilis. Noguchi’s work helped future researchers and doctors better diagnose people with syphilis, assisted them in understanding how to treat the disease’s long-term side effects, and helped them reduce the spread of syphilis, including between pregnant people and their fetuses.

Gonorrhea is a sexually transmitted disease, or STD, caused by the bacterium Neisseria gonorrhoeae. Common symptoms of the disease include painful urination and genital discharge. There are records of historical discussions of gonorrhea in ancient civilizations and during the Middle Ages, but scientists did not begin investigating the scientific causes and treatments of the STD until the sixteenth century. In the 1700s, physicians attributed gonorrhea to the same cause as another STD, syphilis. Later, in the 1800s, researchers discovered the two diseases were not the same and identified the bacteria N. gonorrhoeae that causes gonorrhea. By the 1900s, researchers began using antibiotics to target the bacteria, but many drugs eventually developed antibiotic resistance. In 2020, the World Health Organization, or WHO, estimated that 82.4 million individuals contracted gonorrhea globally, and as of 2024, researchers continue to experiment with various antibiotic drugs to provide adequate treatment for the disease.

Penicillin is a type of drug called an antibiotic that can treat bacterial infections by killing the bacteria or making it difficult for the bacteria to grow. Before the availability of antibiotics, physicians could do little to help patients with bacterial infections, and many of those patients died of those infections. In 1928, Alexander Fleming, a Scottish physician, found a fungus growing in his lab that prevented the growth of certain bacteria. He termed the bacteria-killing substance penicillin. Later researchers built on Fleming’s findings and developed the substance into a drug, which became widely available after 1945. Penicillin was one of the first medications that could safely and effectively treat acute bacterial infections, such as staph infections and strep throat, as well as chronic bacterial infections such as syphilis. Additionally, by studying the mechanism of how penicillin works, researchers have created many other antibiotics. Penicillin and other antibiotics have allowed physicians to treat countless bacterial infections, and to develop new strategies to fight bacterial resistance to those antibiotics, saving the lives of millions.

In 1944, Joseph Earl Moore and colleagues published “The Treatment of Early Syphilis with Penicillin: A Preliminary Report of 1418 Cases,” hereafter “Treatment of Early Syphilis,” in the Journal of the American Medical Association. Moore and colleagues’ article was one of the first to study and explore the use of penicillin, an antibiotic that can kill bacteria, as a treatment for humans with syphilis, which is a bacterial disease that spreads through sexual contact. In its early stages, syphilis can cause rashes and genital sores, but in its late stages, it can also lead to organ damage. In “Treatment of Early Syphilis,” Moore and his colleagues explain that they conducted a study to determine the effects and optimal dose of penicillin in humans with early syphilis. The authors found that giving individuals with syphilis specific doses of penicillin can heal their syphilitic lesions and eradicate the bacterium that causes syphilis from their bodies. “Treatment of Early Syphilis” was one of the first articles to demonstrate that syphilis, specifically early syphilis, could be effectively treated with penicillin, the drug that physicians still most commonly use as of 2024 to treat the sexually transmitted disease.

Philippe Ricord was a nineteenth-century physician and surgeon in France who studied syphilis and demonstrated that it is different from gonorrhea. As of 2024, researchers recognize that syphilis and gonorrhea are both sexually transmitted infections, or STIs. However, the bacterium Treponema pallidum causes syphilis, leading to symptoms such as sores and fever, whereas the bacterium Neisseria gonorrhoeae causes gonorrhea and leads to different symptoms such as discharge from the urethra. Before Ricord, researchers thought syphilis and gonorrhea were the same disease. Ricord, through observation and experimentation, distinguished syphilis from gonorrhea and arranged the stages of syphilis into primary, secondary, and tertiary, each associated with different symptoms and levels of severity. By distinguishing syphilis from other STDs and accurately categorizing its stages, Ricord helped researchers better understand how to treat syphilis, a disease that can be transmitted from mother to child, causing life-threatening illness in infants.