Generalising research findings across different populations is, as trained scientists ought to know, methodologically unsound guesswork. In the case of human medicine the real, the only, test is the stage at which the treatment is applied to the population for which it was ultimately intended. Experimentation on non-human animals for the benefit of the human animal is not, and never will be, methodologically valid.
As an increasingly informed public becomes aware of this, and as scientists respond to growing commercial and academic pressures to produce leading-edge treatments, we can expect the next millennium to be the harbinger of a culture shift in favour of human embryo cloning. Those happy to reap the benefits of experimentation, as long as it is not they themselves who are experimented on, can have no qualms about experiments on human embryo clones (although, they may be afraid to be seen, openly, to support this at present). Scientists will collude, in the name of the same utilitarian principles they currently espouse to justify experimentation on non-human animals - "the suffering of the few is outweighed by the benefits to the many".
The excruciating pain that is felt daily by non-human animals in laboratories throughout the world should be a source of deepest shame on methodological grounds, if not on moral ones.
It is not only the non-human animals that are betrayed, but the humans who remain the final unwitting stage of the experiments. Yet this is the cusp of an equally profound betrayal, the day human embryo cloning for medical experimentation becomes reality. As long as we continue to privilege one species over another, as long as the powerful are allowed to exploit the weak, as long as censorship prevents reference to "torture" and "murder" when debating the rights of non-human animals, human embryo cloning draws inexorably closer.