This book seeks to contribute to a growing literature on the history of eugenics in Latin America by describing eugenic thought in Chile in the first half of the twentieth century. On one axis, it seeks to describe the relationship between two strands of eugenic thought in Chile, one overtly Catholic and the other “secular.” On another axis, it highlights the role of gender in eugenic thought. In addition, the book argues that Chilean eugenics was built around an idea of mestizo national identity while still embracing a commitment to white supremacy. Walsh argues, “Chilean eugenic scientists combined elements from European, North American, and Latin American racial theory and refashioned them to create a particular blend of tolerance for racial mixture in the abstract and preference for European heritage in reality.” (15)

The book is thematically organized into six chapters. The first chapter begins by discussing how Catholic and secular eugenicists agreed in the 1920s and 1930s on the existence of a marriage crisis that threatened the nation's racial health—those who were “fit” seemed not to reproduce. The last third of the chapter, however, is more focused on how secular eugenicists were critical of the role of religion and how Catholic writers responded to such criticism. Chapter 2 describes how Catholic intellectuals—both scientists and non-scientists—made the case that science and Catholicism could be harmonized. Chapter 3 describes differences between Chilean and mainstream North Atlantic eugenics and tries to make the case that Catholic eugenicists contributed to that distinctive character.

Chapter 4 moves back to the early twentieth century to analyze the book Raza chilena by Nicolás Palacios and its peculiar but influential theory that the admixture of Araucanian and Visigothic blood and patriarchal culture had produced a superior “race” in Chile. Chapter 5 returns to the comparison of later Catholic and secular eugenicists to describe how both groups wrote about the need to control sexuality (especially female sexuality) in order to “prevent racial degeneration.” Chapter 6 describes the use of images in eugenicist publications. Walsh argues that these images sought to establish whiteness as normative and associate non-whiteness with abnormality and degeneracy.

The importance of Chilean eugenic thinking in the first half of the twentieth century is undeniable. Politicians and intellectuals frequently framed their ideas and policy proposals in terms of the “defense of the race” or the “preservation of the race.” So, this book is a welcome contribution, as are Walsh's many related journal articles on the theme. But the book fails to convince that Catholic eugenicists were uniquely responsible for the distinctiveness of Chilean eugenic thought. At no point does the book offer a clear example of how Catholic eugenicists altered or inflected opinions held by secular eugenicists. Furthermore, the fourth chapter, on Palacios, illustrates how Chilean eugenic thinking was already quite distinctive before the Catholic eugenic movement gained steam.

Walsh is more convincing with her various discussions of how eugenicists put a surprising emphasis on the defense of traditional gender norms. She makes a particularly insightful observation about the centrality of patriarchy to Palacios's racial theory. Chapter 5 also offers an interesting description of how later eugenicists saw male sexual behavior as problematic but put the onus on women to channel this behavior and curb its dysgenic effects. One could imagine some more progressive lines of eugenic thinking in gender terms in the Chilean context, but Walsh shows that Chile's eugenicists saw a need to shore up ideals of manliness and traditional femininity against the threats posed by modern cultural practices and spaces.