The opening scenario in Week 5 presents one of several ethical questions and dilemmas that genetics raises for health care. Problems also follow from our ever-increasing mastery of genetic engineering, including the ability to manipulate the human genome, so that we can "edit" eggs, sperm, or embryos to make genetically modified children. Should people be allowed to request gene-edited babies? Although the technology is not quite there yet for that to be an immediate problem, it's not far off. Another set of ethical questions surrounds our current use of embryonic stem cells. The article by Michael Sandel ("Embryo EthicsThe Moral Logic of Stem-Cell Research") in this week's What You Need to Know provides a compelling ethical defense of their use.

• Which moral theories,ethical principles, or both are most relevant to understanding and perhaps answering these questions?