Endocrine disruptors are chemicals that interact with the hormone system to negative effect. They ‘disrupt’ normal processes to cause diseases like vaginal cancer and obesity, reproductive issues like t-shaped uteri and infertility, and developmental abnormalities like spina bifida and cleft palate. These chemicals are ubiquitous in our daily lives, components in everything from toothpaste to microwave popcorn to plastic water bottles. My dissertation looks at the history, science, and regulation of these impactful substances in order to answer the question of how endocrine disruptors appeared, got interpreted by different groups, and what role science played in the process. My analysis reveals that endocrine disruptors followed a unique science policy trajectory in the US, rapidly going from their proposal in 1991 to their federal regulation in 1996, even amid intense and majority scientific disagreement over whether the substances existed at all. That trajectory resulted from the work of a small number of scientist-activists who constructed a concept and category as scientific, social, and regulatory. By playing actors from each sphere against each other and advancing a very specific scientific narrative that fit into a regulatory and social window of opportunity in the 1990s, those scientist-activists made endocrine disruptors a national issue that few could ignore. Those actions resulted in the Endocrine Disruptor Screening Program, a heavily-criticized and ineffective regulatory program. My dissertation tells a story of the past that informs the present. In 2018, the work of researchers, public media, and policymakers in the 1990s continues to play out, evident in the deep scientific division over endocrine disrupting effects and the inability of the European Union to settle on even a definition of endocrine disruptors for regulation purposes.

This study takes biophysics--a relatively new field with complex origins and contested definitions--as the research focus and investigates the history of disciplinary formation in twentieth-century China. The story of building a scientific discipline in modern China illustrates how a science specialty evolved from an ambiguous and amorphous field into a full-fledged academic discipline in specific socio-institutional contexts. It focuses on archival sources and historical writings concerning the constitution and definition of biophysics in order to examine the relationship between particular scientific styles, national priorities, and institutional opportunities in the People's Republic of China. It argues that Chinese biophysicists exhibited a different style of conceiving and organizing their discipline by adapting to the institutional structure and political economy that had been created since 1949. The eight chapters demonstrate that biophysics as a scientific discipline flourished in China only where priorities of science were congruent with political and institutional imperatives. Initially consisting of cell biologists, the Chinese biophysics community redirected their disciplinary priorities toward rocket science in the late 1950s to accommodate the national need of the time. Biophysicists who had worked on biological sounding rockets were drawn to the military sector and continued to contribute to human spaceflight in post-Mao China. Besides the rocket-and-space missions which provided the material context for biophysics to expand in the late 1950s and early 1960s, Chinese biophysicists also created research and educational programs surrounding biophysics by exploiting the institutional opportunities afforded by the policy emphasis on science's role to drive modernization. Biophysics' tie to nationalistic and utilitarian goals highlights the merits of approaching modern Chinese history from disciplinary, material, and institutional perspectives.