Existing education histories highlight how, in the final years of the twentieth century, prominent economists influentially argued that girls’ education was an urgently needed development intervention for countering rapid population growth. However, this newfound focus on girls’ education as a tool for managing reproduction arose at a perplexing time in which social scientists were largely turning their attention away from concerns over population growth. In fact, in the late twentieth century, many economists and demographers moved towards asserting that population growth was not an urgent problem. Through archival research and oral history interviews with social scientists, this study examines the evolution of two quantitative social science disciplines—economics and demography—from 1970 to the turn of the twenty-first century. Disrupting notions of scientific consensus, this research illuminates how social scientists in this period advanced and debated divergent views on the relationships between girls’ education, population growth, and economic growth.