Henry Herbert Goddard was a psychologist who conducted research on intelligence and mental deficiency at the Vineland Training School for Feeble-Minded Boys and Girls in Vineland, New Jersey during the early twentieth century. In 1908, Goddard brought French psychologist Alfred Binet and physician Theodore Simon’s intelligence test to the US and used it to investigate intellectual disability in children at the Vineland Training School for Feeble-Minded Boys and Girls. Goddard also wrote a book in 1912 called The Kallikaks: A Study in the Heredity of Feeble-Mindedness, claiming that traits like mental deficiency were heritable traits. His observations and research led Goddard to advocate for sterilization and segregation of the intellectually disabled, which were ideas that reflected the emerging eugenics movement in the US, during the early nineteenth century. Although by the end of his life, psychologists largely dismissed Goddard’s work, schools and the US military used Goddard’s version of Binet and Simon’s intelligence test to identify mental deficiency.

The copper intrauterine device, or IUD, is a long-term, reversible contraceptive first introduced by Howard Tatum and Jamie Zipper in 1967. Health care providers place an IUD inside a woman’s uterus to prevent pregnancy. Copper IUDs are typically made of T-shaped plastic with some portion covered with exposed copper. Prior to the invention of the first IUDs, women had few long-term options for safe and reliable birth control. Those options mostly consisted of barrier methods and the oral birth control pill, which were only effective if used correctly and consistently. For women seeking to control their fertility, a copper IUD was one of the first forms of long-term birth control that was highly effective and did not require consistent and regular action on the woman’s part to remain effective.

In the 1973 case of Roe v. Wade, the US Supreme Court ruled that laws banning abortion violated the US Constitution. The Texas abortion laws, articles 1191–1194, and 1196 of the Texas penal code, made abortion illegal and criminalized those who performed or facilitated the procedure. Prior to Roe v. Wade, most states heavily regulated or banned abortions. The US Supreme Court decision in Roe v. Wade secured women's rights to terminate pregnancies for any reasons within the first trimester of pregnancy. It also sparked legal discussions of abortion, fetus viability and personhood, and the trimester framework, setting a landmark precedent for future cases including Webster v. Reproductive Health Services (1989), Planned Parenthood v. Casey (1992), and Stenberg v. Carhart (2000).

Charles Benedict Davenport, Madison Grant, and Henry Fairfield Osborn founded the Galton Society for the Study of the Origin and Evolution of Man, or the Galton Society, in New York City, New York, in 1918. The Galton Society was a scientific society that promoted the study of humans in terms of race in service to the US eugenics movement. The Galton Society was named in honor of Francis Galton who first coined the term eugenics in 1883. Galton and other eugenics proponents claimed that the human species could improve through selective breeding that restricted who could have children. Some of the society members were scientists from a wide range of disciplines who supported the now disproven notion that fundamental biological differences exist between races that may justify the control of human reproduction. The Galton Society drew on the scientific credibility and influence of its members to advocate for eugenics programs, such as immigration restriction laws, in the US.

In the early twentieth century, Paul Kammerer conducted a series of experiments to demonstrate that organisms could transmit characteristics acquired in their lifetimes to their offspring. In his 1809 publication, zoologist Jean-Baptiste Lamarck had hypothesized that living beings can inherit features their parents or ancestors acquired throughout life. By breeding salamanders, as well as frogs and other organisms, Kammerer tested Lamarck's hypothesis in an attempt to provide evidence for Lamarck's theory of the inheritance of acquired characteristics. In particular, Kammerer argued that the inheritance of acquired characteristics caused species to evolve, and he claimed that his results provided an explanation for evolutionary processes through developmental phenomena.

In the first decade of the twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, conducted research on developmental mechanisms, including a series of breeding experiments on toads (Alytes obstetricans). Kammerer claimed that his results demonstrated that organisms could transmit acquired characteristics to their offspring. To explain how evolution occurred, biologist Jean-Baptiste Lamarck in France suggested in his 1809 book that offspring inherited the features their ancestors acquired throughout the lives of those ancestors, a process termed the inheritance of acquired characteristics. Kammerer conducted breeding experiments to test the theory of inheritance of acquired characteristics, which he said described the mechanics of evolution. Additionally, Kammerer's experiments aimed at explaining how development shaped evolutionary processes.

Friedrich Leopold August Weismann published Das
Keimplasma: eine Theorie der Vererbung (The Germ-Plasm: a
Theory of Heredity, hereafter The Germ-Plasm) while
working at the University of Freiburg in Freiburg, Germany in 1892.
William N. Parker, a professor in the University College of South
Wales and Monmouthshire in Cardiff, UK, translated The
Germ-Plasm into English in 1893. In The Germ-Plasm,
Weismann proposed a theory of heredity based on the concept of the
germ plasm, a substance in the germ cell that carries hereditary information. The
Germ-Plasm compiled Weismann's theoretical work and analyses of
other biologists' experimental work in the 1880s, and it provided a
framework to study development, evolution and heredity. Weismann
anticipated that the germ-plasm theory would enable researchers to
investigate the functions and material of hereditary substances.

In the early twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, experimented on sea-squirts (Ciona intestinalis). Kammerer claimed that results from his experiments demonstrated that organisms could transmit characteristics that they had acquired in their lifetimes to their offspring. Kammerer conducted breeding experiments on sea-squirts and other organisms at a time when Charles Darwin's 1859 theory of evolution lacked evidence to explain how offspring inherited traits from their parents. In 1809, zoologist Jean-Baptiste Lamarck in France theorized that living beings can inherit the features their parents or ancestors acquired during those ancestor's lifetime, a theory called the inheritance of acquired characteristics. Kammerer attempted to provide evidence for the theory of inheritance of acquired characteristics, which constituted, he argued, the mechanics of evolution. Kammerer claimed that his results could explain evolutionary processes through developmental phenomena.

Margaret Goldwater advocated for birth control and reproductive rights in the United States during the twentieth century. Goldwater was a socialite and philanthropist and was married to Barry Goldwater, US Senator from Arizona. She spent much of her life working to further the women's reproductive rights movement, which sought to expand women's legal, social, and physical access to reproductive healthcare, including contraception and abortions. Goldwater, with guidance from birth control activist Margaret Sanger, helped establish the second birth control clinic in Arizona, the Mother's Health Clinic in Phoenix, Arizona. She conducted large fundraising events and authored articles in local newspapers on the need for contraceptives and family planning. Goldwater's advocacy helped launch and sustain The Mother's Health Clinic, which became the largest provider of women's reproductive healthcare in Arizona, and it later became Planned Parenthood of Central and Northern Arizona.

The Malthusian League, founded in London, England, in 1877 promoted the use of contraception to limit family size. Activists Charles Bradlaugh and Annie Besant established the Malthusian League after they were arrested and exonerated for publishing a pamphlet describing techniques to prevent pregnancy. Founders based the league on the principles of Thomas Malthus, a British nineteenth century economist, who wrote on the perils of a population growing beyond the resources available to support it. The Malthusian League advocated for limiting family size voluntarily through contraception to avoid the overpopulation and poverty cautioned in Malthus’ work. After fifty years, the Malthusian League closed due to the increasing disapproval for Malthus’s economic theories of population and poverty. However, the Malthusian League’s activism during the late nineteenth and early twentieth centuries led to more tolerant views of contraception and family planning in Great Britain in the twentieth century.