This article explores some of the potential moral and social ramifications of the Human Genome Project. Research on the human genome is generating important ethical and social questions of at least three distinct kinds. First, what genetic information should be generated, and who should control its dissemination and use? Improved diagnostic techniques such as presymptomatic testing, carrier screening, and prenatal screening can provide information that poses significant ethical problems for individuals, employers and insurance companies, and the medical and counseling professions. Second, what genetic procedures should be employed? The burgeoning ability to manipulate human genotypes and phenotypes through procedures such as gene therapy and enzyme therapy are leading to difficult questions about which manipulations should be permitted and which should be prohibited. Third, how will this new information change lives? Increasing claims about the relationship of genetics to ethically and politically significant traits and behaviors are challenging human self-understanding and the capacity of social institutions to respond adequately.