Sharon M. Leon's An Image of God: The Catholic Struggle with Eugenics analyses how American Catholics fought against eugenics at a time when it had significant influence on American culture and legislation. Using institutional records, personal papers and periodicals produced by both Catholics and eugenicists, Leon contends that balancing the needs of the individual with those of the common good became the main preoccupation for American Catholics when objecting to eugenic legislation. Focusing on the years between 1910 and 1950, she argues that religious pluralism in the United States forced Catholics to discredit eugenics on a scientific basis, rather than on moral grounds. As a result, Catholics moved out of relative social and political isolation at the beginning of the twentieth century to become one of the most visible religious groups in the country in just a few decades.

Leon explores Catholic opposition to the implementation of eugenic sterilization of wards of the state, arguing that Catholics became the first Americans to realize the potential pitfalls of eugenic legislation. From the start, they questioned the role that the state should play in reproductive health and choice by insisting upon the integrity of all human bodies regardless of heredity. Catholic critics were concerned that there was neither a legal nor a moral precedent for state-funded eugenic procedures such as sterilization, leaving them open to manipulation by politicians and state functionaries. To address their displeasure, the American Eugenics Society sought the support of religious figures by forming the Committee on Cooperation with Clergymen. Though representatives of other religious groups were generally in favour of eugenics, Catholic members of this committee (Reverends John A. Ryan and John Montgomery) were not: ‘the church's teaching maintained that Catholics were united – regardless of racial and ethnic differences – through their commitment to a common faith and a sacramental theology’ (p. 48). The author seems to take these views at face value, but provides evidence that implies that race played a more central role in American Catholicism than she discusses.

Leon notes that there were very few African American Catholics and that most practising Catholics in the United States belonged to a tapestry of white European ethnic groups. This suggests that race did matter to American Catholics, even if the individuals that Leon studies did not articulate it. Perhaps this issue arises because Leon characterizes eugenic science as a primarily white and North Atlantic discipline, reaffirming the diametric opposition between eugenics and Catholicism that she employs in her monograph. A discussion of the complexities that must have faced American Catholics advocating a type of racial blindness while living in a country deeply committed to racial segregation would have added depth to this work.

When discussing, in her third chapter, how Catholic efforts to halt forced sterilization legislation passed in the United States between 1924 and 1933 did not rely on moral arguments, Leon's work is much more nuanced. They instead emphasized scientific flaws in eugenic principles and abuses against social justice in forced medical procedures. These objections were mostly ad hoc prior to the 1930 papal encyclical Casti Connubi, which officially declared the Church's anti-sterilization position. Chapter 4 examines the role that international events played in the work of both American eugenicists and Catholics. The American government's encouragement of birth control and sterilization programmes in Puerto Rico, during the 1930s, forced mainland American Catholics to publicly denounce projects they believed were designed to establish a racial hierarchy. In presenting these arguments, Leon illuminates how Catholic understandings of social justice caused American Catholics to reject eugenic legislation, but without reflecting upon its implications within a racialized American context.

Returning to the continental United States, the final two chapters focus on how Catholics gained ground over the course of the 1930s and 1940s in their anti-eugenics efforts: ‘The attention to the sterilization movement and the scientific critiques of it, in combination with the participation of Catholic intellectuals in secular debates, contributed to a more widespread opposition to eugenic sterilization’ (p. 139). Though the scarcity of resources caused by the Great Depression might suggest an increase in the popularity of eugenic legislation, Leon shows that forced sterilization was increasingly unpopular even among secular Americans. Catholic critics began appearing in mainstream publications as experts voicing their disagreement with sterilization. They were no longer marginal players in the American political and cultural landscape. But their fears about eugenics did not mean that they were champions of progress in all areas. Catholic critics also feared that the Depression and the Second World War had had profound effects on the nation in the form of gender disorder. Chapter 6 reveals that this concern made strange bedfellows of anti-eugenic Catholics and some members of the American Eugenics Society. Ultimately, though, Catholics and eugenicists could not agree because of their opposed beliefs about racial hierarchy.

Adding depth and complexity to the history of eugenics in the United States, Leon's work is a valuable contribution to the growing literature regarding Catholicism and science in the twentieth century. Yet Leon's story sometimes skews towards a more noble portrayal of the American Catholic Church than is probably fair. For example, she credits American Catholics with seeming ‘intuitively aware of the broad constellation of issues beneath the seemingly straightforward desires of eugenicists' (p. 167). Generalizations of this type are hard to prove, and unnecessary. Her book is already valuable because it details how American Catholics condemned eugenics specifically because of its racist elements, at a time when the United States was racist both politically and culturally. It is rare to see historical writing that puts Catholics on the winning side of any conflict in the twentieth century and Leon's is an excellent example of what we can learn when we avoid making assumptions about Catholicism.