One of the earliest attempts to square this circle of trying to conduct morally problematic research within ethical guidelines is the “14-day rule” for embryo research. The rule has allowed embryo research outside the womb for up to 14 days post-fertilization, after which time the embryo would be destroyed. Although the origins of the rule go back over 40 years, it has been much in the news lately as scientists have developed methods to considerably extend the life of embryos outside the womb.