Despite some recent suggestions to the contrary, it now appears that Dolly (see Nature 385, 810–813; 1997) was indeed a clone produced from the nucleus of a differentiated cell derived from an adult sheep. Those who questioned that conclusion can now accept it in the light of experiments, including DNA analysis of original tissues, reported in the Scientific Correspondence section of this issue (see page 329). Circumstantial evidence is also added by the fact that the trick has been accomplished again, this time with mice (page 369). The conclusion for developmental biologists remains fascinating: the differentiation of cells is in some cases reversible — the expression of their genomes can be reprogrammed to that of the undifferentiated state. As Davor Solter describes (page 315), the new results sharpen the scientific challenge to be addressed.

But the results also highlight progress in the face of pessimism about the technical obstacles. They throw into sharp relief the response of some researchers to the concerns expressed by others about human cloning, namely that the technological capability is a long way off, and the practical obstacles apparently insuperable. That response looks like becoming irrelevant all too quickly.

Thus it becomes all the more probable that, where someone is legally allowed to do it, they will. After all, there are, as Solter bullishly describes, potential benefits. And one country where human cloning is in principle legal, despite strong opposition, is the United States. Only federal funding of such work is banned.

Republicans in Congress have attempted to prohibit altogether not only the gestation and bringing to birth of human clones, but also experiments at the pre-implantation stage — an initiative that was successfully derailed by the scientific community. A bill that would permit pre-implantation research has been proposed, but progress is unlikely before Congress breaks up in early October.

Private companies are free to make their move. Debates continue over the protection of the unborn, while the technology moves on. Given the demonstrable potential for moral panic in this field, it is regrettable, and not in the best interests of science, that the world's scientific superpower has so far failed to deliver a satisfactory contract between researchers and its citizens at large on this issue.