Prevention and treatment of inherited diseases have advanced exponentially as we learn more about their genetic bases. However in many cases prevention relies on discarding embryos or terminating pregnancies. If we can alter the genetics that cause the disease so that the defective gene is no longer present in family members, then the disease disappears from that family forever. Why would we not want to do this and what does Judaism have to do with these decisions? What are the risks and what else might we want to do with these technologies once we know how to use them? Where should we fear to tread?