Abstract

Mammalian one-cell embryos can be genetically altered, implanted into the female's uterus, and subsequently develop into biologically mature organisms in the usual manner. If the resultant adult organisms reproduce, the genetic change may be passed on to future generations. In humans, the procedure is known alternatively as "human genetic engineering" or "human germline gene therapy." Bioethicists distinguish between genetic engineering intended for the prevention or treatment of disease and genetic engineering intended for non-medical enhancement of certain characteristics . Human genetic engineering has the potential to effectively replace deleterious genes---such as the gene for cystic fibrosis or sickle cell disease---with a normal gene. Thus, not only is disease avoided in the next generation, but all future generations are spared the effects of the disease-causing gene as well. ;The current public policy consensus is that human genetic engineering, whether intended for treatment or enhancement, is ethically impermissible. The primary reason is that present genetic engineering technology carries an unacceptable level of risk for use in humans. There is, however, good reason to believe that genetic engineering will become acceptably safe for use in humans, thereby eliminating the major ethical barrier to the technology. In fact, several policy statements already have suggested that, once safe, treatment genetic engineering ought to be permitted while enhancement genetic engineering ought not to be permitted. ;Part of the concern surrounding genetic enhancement is that bad consequences---such as morally objectionable eugenics practices---might ensue. But another objection is that human genetic enhancement is intrinsically problematic. In other words, at least very radical genetic enhancements violate what it is that makes human beings intrinsically valuable. Drawing on a Wittgensteinian view of human beings, the present work proposes a conception of ethically significant humanness---"human beingness"---that is potentially threatened by certain kinds or degrees of human genetic enhancement. The impact of human beingness on the future direction of human gene therapy policy, and in other policy areas, is discussed