This book is the third and last volume in Dr Theodoor Hendrik van de Velde’s trilogy on the problems of marriage and this book completes his internationally authoritative work on eugenics and volitional sex behavior. Following his other book this book considers such problems as sexual abstinence and excess, family limitation, the achievement of desired pregnancy, the causes and consequences, physically and emotionally, and sterility in women and impotence in men, artificial insemination, and the delicate personal and social aspects of undesired conception. Scientific in its approach and simple in its presentation, this book is for doctors and laymen. It offers information that contributes to a healthier understanding of voluntary and planned conception and helps safeguard happiness in marriage.