Salt Lake City, UT – As a child, Utah geneticist Mario Capecchi roamed the streets of war-torn northern Italy. He survived by stealing and begging for food. That early misfortune ignited his fierce independence and tenacity that would later serve him well as a scientist. Capecchi experienced an overwhelming lack of support from the science community during the early progress of his ground-breaking ideas, but his persistence brought the world a brand-new technology called gene targeting. This technique is tremendously powerful for investigating how genes work. With precise control, scientists can now creat and study animal models of human development and disease, but becasue this technology also has the potential for opening the door to genetic engineering in animals and humans, ethical questions arise. In the final segment of our series on Mario Capecchi, producer Sheri Quinn examines the ethical issues raised by gene targeting.