Dolly Confirmation

It has now been almost a year since the cloning of the sheep Dolly from an adult ovine cell was announced (1). The year has brought much agonizing discussion, potential legislation, and some laurels, but no more Dollies. The principal scientist, Ian Wilmut, has announced (2) that he and his group have no intention of trying again (to clone using mammary DNA and a host denucleated ovine cell). Some “very soon” to be delivered (3) cows that were to be cloned from adult cells have yet to appear. Other rumored events seem also to have dissipated. It is a well-known tenet of science that a single observation is not to be codified until confirmed by someone in some way. The single observation gains some credence when well controlled or of a unique nature, or both. It is the lack of any confirmation that provokes our skepticism; here are some of the detailed reasons.