Abstract

This chapter focuses on a limit that was defined in the early days of IVF and which for nearly four decades was widely affirmed and adopted. This is the so called fourteen-day rule. It designates that human embryos should not be cultured in vitro beyond fourteen days of development. The fourteen-day rule has long been offered as an assurance that scientific horizons are subject to ethical limits. Over the course of several decades, it has also become a matter for relatively widespread consensus. Although there remains significant disagreement about whether instrumental use of human embryos for research can ever be acceptable and about what sort of limits, temporal or otherwise, it ought to be subject to, the fourteen-day rule has long formed a centerpiece of policies in numerous countries that affirm ethical concerns while also allowing room for research by marking fourteen days as a definitive limit.