This dissertation investigates the ways scientific and biotechnological advancement impact and change Jewish law and ethics. It analyzes the contemporary Jewish bioethical debate concerning the identification of maternity and paternity in four cases of assisted reproductive technologies (ART): in vitro fertilization, gestational surrogacy, cloning, and mitochondrial replacement therapy. Unprecedented modes of procreation engender new definitions of parenthood, challenging a longstanding Jewish framework of theology, law, and ethics. Part I develops a conceptual scaffolding for the discrete analyses of Part II, and considers the philosophical bases of parenthood, the gendered nature of Jewish legal bioethics, the relationship of law and ethics, and ways of relating religion and science. For each case of ART, Part II examines the biological science and technology in historical context, locates Jewish bioethical concerns within the larger bioethical discussion, and critically reviews the epistemological and axiological dimensions of the legally oriented analyses of a select group of leading Jewish bioethicists, chosen for their copious writings on ART and contextualizing oeuvres: Rabbi J. David Bleich, Rabbi Michael J. Broyde, Rabbi Elliot N. Dorff, and the collaborative writings of Dr. John D. Loike and Rabbi Moshe D. Tendler. Insights from Jewish feminist bioethical criticism and other notable Jewish bioethical works enhance the analyses. Through a focused study of the redefinition of parenthood in Jewish law and bioethics, I demonstrate four ways in which advances in science impact Jewish law and ethics. One, scientific awareness leads to greater sophistication and nuance of analysis. Two, Jewish bioethicists grapple with religion and science relations, and speak directly to these overarching considerations. Three, the epistemological and axiological influence of religion and science relations correlate with greater openness to new technologies, theoretical conceptualizations, and their practical applications. Four, advances in science change Jewish legal and bioethical analyses and outcomes through (at least) four possible methodological mechanisms – namely, theoretic holism, innovative interpretation, indeterminate gaps, and realist realignment. Jewish bioethics are thus shown to illumine the intricate interrelationship between religion and science and its impact on Jewish law and ethics.