This book offers a unique and comprehensive outline of the ethos, the bioethics and the sexual ethics of the renowned anatomist and founder of modern geology, Niels Stensen (1638-1686). It tells the story of a student who is forced to defend himself against his professor who tries to plagiarize his first discovery, the "Ductus Stenonis": the first performance test for the young researcher. The focal points are questions of bioethics, especially with regard to human reproduction, sexual ethics, the beginning of life and the ensoulment of the embryo, together with frontiers of pastoral care. The book delineates Stensen''s ethos as well as its medico-ethical and theological implications and reception by researchers and physicians from the 17^th century until today, and asks about his lasting significance. Despite dating back more than 300 years, Stensen''s character and his work offer up surprisingly topical answers to current questions on the nature of professional ethics in medical science and practice. Furthermore, "Ethos, Bioethics, and Sexual Ethics in Work and Reception of the Anatomist Niels Stensen (1638-1686): Circulation of Love" is the first academic book on bioethics and sexual ethics with a foreword by the Prefect of the Congregation for the Doctrine of the Faith. A fascinating book for bioethicists, physicians, members of health professions, scientists, and theologians.