The project explores the transatlantic history of family planning based on the entanglements of the Planned Parenthood Federation of America and the West German organization Pro Familia. It analyzes how the idea of family as something to plan for was established in two different Western societies. In the first third of the twentieth century, advocates of birth control only intervened in families when they already had several children; however, beginning in the 1940s, Planned Parenthood established the idea that families could be planned from the very beginning of marriages. This concept circulated to the Federal Republic when Pro Familia was founded in 1952. German sexual reformers in exile brought knowledge about the newest developments of various means of birth control to the United States. Thus, the project utilizes approaches to the history of knowledge to analyze the processes of knowledge exchange among the family planning organizations in West Germany and the United States concerning contraceptives and abortion methods, feminist knowledge about possibilities of sterilization abuse, and the concept of the “wanted child.” The question of who has the right to make a reproductive choice is central to conflicts about contraceptives and the legalization of abortion. Consequently, the project asks how having children came to be conceptualized as resulting from decision-making processes. In this way, the project makes a contribution to the study of how concepts of the family and the role of individualistic and collective motives in processes of social decision-making were transformed. The plan for the monograph includes the following chapters: The first chapter outlines the contacts between the American Birth Control Movement and the Sex Reform Movement in the Weimar Republic and the attitudes of sex reformers towards National Socialism. Chapter 2 demonstrates how Planned Parenthood established the idea of family planning in the United States. Chapter 3 discusses how the concept of family planning was introduced in the Federal Republic of Germany. Chapter 4 explores the ways that both organizations dealt with minorities and sterilization, whereas Chapter 5 illuminates the introduction of oral contraceptives to the market in 1960. Chapter 6 analyzes the transnational connections within the women’s movement in its criticism of oral contraceptives, while Chapter 7 addresses the international reform processes of abortion in the 1970s. Chapter 8 takes up the opposition to legal abortion, which, with its demand for “informed consent,” reinforced the practice that women were the ones to decide about an abortion in the end. With this structure, the book presents the transnational entanglements that led to a shift in the idea of family on both sides of the Atlantic from a long-term perspective.