Be Fruitful and Multiply examines the moral justification offered by Anglican leaders for their support for eugenic, pronatalist, and neo-Malthusian schemes in the United Kingdom during the interwar period. These religious leaders often comprehended their efforts to control fertility within the context of a broader struggle over competing conceptions of human purpose in English society, and regularly justified their efforts on the grounds that fertility-manipulation schemes served to align procreative behaviors with “Christian” conceptions of human purpose. The shared moral logic of Anglican leaders helps to explain the pervasive interest in birthrate patterns, along with the enduring appeal of fertility-manipulation schemes, amongst middle- and upper-classes during the first half of the twentieth century. This book also sheds light on how population concerns led to the liberalization of church positions on marriage and sexuality, and illuminates how Anglican leaders sought to maintain moral influence in the face of the perceived large-scale rejection of Christian moral teachings.