Breast cancer affects about 12% of women in the US. Arguably, it is one of the most advertised cancers. Mammography became a popular tool of breast cancer screening in the 1970s, and patient-geared guidelines came from the American Cancer Society (ACS) and the US Preventative Task Force (USPSTF). This research focuses on ACS guidelines, as they were the earliest as well as the most changed guidelines. Mammography guidelines changed over time due to multiple factors. This research has tracked possible causes of those changes. Research began with an extensive literature search of clinical trials, the New York Times and the Washington Post archives, systematic reviews, ACS and USPSTF archives.

In the early 2000s, Richard S. Legro, Mark V. Sauer, Gilbert L. Mottla, Kevin S. Richter, William C. Dodson, and Duanping Liao studied the relationship between air pollution and reproductive complications. In the United States, Legro’s team tracked thousands of women undergoing in vitro fertilization, or IVF, along with the air quality of both the IVF clinics and patients’ home locations. IVF is a reproductive technology during which a physician obtains mature eggs from a patient’s ovaries and fertilizes them with sperm in a lab setting outside of the body, after which the physician transfers the fertilized eggs into the patient’s uterus. As stated in Legro’s publication, Legro suspected that poor air quality would adversely affect live birth rates during IVF, so he compiled and analyzed the various types of pollutants that IVF patients were naturally exposed to in their homes and clinics. Legro’s experiment led to an increased awareness among patients about the dangers of conceiving via IVF in highly polluted areas.

Between February 1969 and August 1970 Edward Kollar and Grace Baird, from the University of Chicago in Chicago, Illinois, published three papers that established the role of the mesenchyme in tooth induction. Drawing upon a history of using tissue interactions to understand differentiation, Kollar and Baird designed their experiments to understand how differentiated structures become specified. Their work overturned a widely accepted model that epithelium controls the identity of the structure, a phenomenon called structural specificity. Interactions between epithelium and mesenchyme control the development and differentiation of many parts during embryonic development, including structures like the gastrointestinal tract and hair. Thus, the realization that mesenchyme drives induction and differentiation during epithelio-mesenchymal interactions had far-reaching effects.

This thesis shows us the history of how some of the first attempts at IVF in humans using various options such as donated egg cells and cryopreserved embryos, often ended in early miscarriages. At that time, most members of the scientific community and general public responded to those trials by regarding them as insignificant. In 1998, the success rate of women under the age of 38 having children with the use of IVF was 22.1%. Over time, scientists began to acknowledge those published findings that detailed various “failed” human IVF experiments. Scientists learned to use them as a guide for what to do differently in future IVF experiments. Because of that, scientists have since developed more effective IVF methods which have ultimately improved the procedure’s success rate.

The Silent Scream is an anti-abortion film released in 1984 by American Portrait Films, then based in Brunswick, Ohio. The film was created and narrated by Bernard Nathanson, an obstetrician and gynecologist from New York, and it was produced by Crusade for Life, an evangelical anti-abortion organization. In the video, Nathanson narrates ultrasound footage of an abortion of a twelve-week-old fetus, claiming that the fetus opened its mouth in what Nathanson calls a silent scream during the procedure. As a result of Nathanson's anti-abortion stance in the film, The Silent Scream contributed to the abortion debate in the 1980s.

In 2003, Carmina Gisbert and her research team produced a tobacco plant that could remove lead from soil. To do so, they inserted a gene from wheat plants that produces phytochelatin synthase into a shrub tobacco plant (Nicotiana glauca) to increase N. glauca's absorption and tolerance of toxic metals, particularly lead and cadmium. Gisbert and her team aimed to genetically modify a plant so that it could be used for phytoremediation- using plants to remove toxic substances from the soil. Scientists have identified phytoremediation as an effective and efficient process to improve human health and reproductive health in contaminated areas. Metals like mercury and lead can cause birth defects during human development like cognitive impairment, cerebral palsy, deafness, tremors, and blindness.

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.

Sir John Bertrand Gurdon further developed nuclear transplantation, the technique used to clone organisms and to create stem cells, while working in Britain in the second half of the twentieth century. Gurdon's research built on the work of Thomas King and Robert Briggs in the United States, who in 1952 published findings that indicated that scientists could take a nucleus from an early embryonic cell and successfully transfer it into an unfertilized and enucleated egg cell. Briggs and King also concluded that a nucleus taken from an adult cell and similarly inserted into an unfertilized enucleated egg cell could not produce normal development. In 1962, however, Gurdon published results that indicated otherwise. While Briggs and King worked with Rana pipiens frogs, Gurdon used the faster-growing species Xenopus laevis to show that nuclei from specialized cells still held the potential to be any cell despite its specialization. In 2012, the Nobel Prize Committee awarded Gurdon and Shinya Yamanaka its prize in physiology and medicine for for their work on cloning and pluripotent stem cells.

Mesoderm is one of the three germ layers, groups of cells that interact early during the embryonic life of animals and from which organs and tissues form. As organs form, a process called organogenesis, mesoderm interacts with endoderm and ectoderm to give rise to the digestive tract, the heart and skeletal muscles, red blood cells, and the tubules of the kidneys, as well as a type of connective tissue called mesenchyme. All animals that have only one plane of symmetry through the body, called bilateral symmetry, form three germ layers. Animals that have only two germ layers develop open digestive cavities. In contrast, the evolutionary development of the mesoderm allowed in animals the formation of internal organs such as stomachs and intestines (viscera).