The revolution in DNA technology has permitted the development of otherwise unavailable and novel biological medicines; has provided new and efficient methods for the large-scale production of existing substances; is the basis for novel, highly sensitive and specific diagnostic tests; has developed new techniques in genetic engineering; is the basis for the development of new and safer vaccines, which are more effective and can be produced in larger quantities than by any other means; is a major key. to new fundamental understanding of normal and disease processes. As far as risks are concerned, a few examples will be mentioned, related to biotechnology-derived products (biologicals), human embryonic stem cells, gene therapy and application of functional genomics. As a final step, the so-called precautionary principle will be introduced, since it raises a cluster of questions about how prudently to engage in risk-taking.