[Cloning] can't make you immortal because clearly the clone is a different person. If I take twins and shoot one of them, it will be faint consolation to the dead one that the other one is still running around, even though they are genetically identical. So the road to immortality is not through cloning.

As immoral and unethical as this may be [to clone a human], there is a real chance that could have had some success. This is a pure numbers game. If they have devoted enough resources and they had access to enough eggs, there is a distinct possibility. But, again, without any scientific data, one has to be extremely skeptical.
Commenting on the announcement of the purported birth of the first cloned human.

Fertilization of mammalian eggs is followed by successive cell divisions and progressive differentiation, first into the early embryo and subsequently into all of the cell types that make up the adult animal. Transfer of a single nucleus at a specific stage of development, to an enucleated unfertilized egg, provided an opportunity to investigate whether cellular differentiation to that stage involved irreversible genetic modification. The first offspring to develop from a differentiated cell were born after nuclear transfer from an embryo-derived cell line that had been induced to became quiescent. Using the same procedure, we now report the birth of live lambs from three new cell populations established from adult mammary gland, fetus and embryo. The fact that a lamb was derived from an adult cell confirms that differentiation of that cell did not involve the irreversible modification of genetic material required far development to term. The birth of lambs from differentiated fetal and adult cells also reinforces previous speculation that by inducing donor cells to became quiescent it will be possible to obtain normal development from a wide variety of differentiated cells.
[Co-author of paper announcing the cloned sheep, ‘Dolly’.]

Science can tell you how to clone a tyrannosaurus rex. Humanities can tell you why this might be a bad idea.

The pressures for human cloning are powerful; but, although it seems likely that somebody, at some time, will attempt it, we need not assume that it will ever become a common or significant feature of human life.

They tend to be suspicious, bristly, paranoid-type people with huge egos they push around like some elephantiasis victim with his distended testicles in a wheelbarrow terrified no doubt that some skulking ingrate of a clone student will sneak into his very brain and steal his genius work.

Thus will the fondest dream of Phallic science be realized: a pristine new planet populated entirely by little boy clones of great scientific entrepreneurs free to smash atoms, accelerate particles, or, if they are so moved, build pyramids—without any social relevance or human responsibility at all.

What politicians do not understand is that [Ian] Wilmut discovered not so much a technical trick as a new law of nature. We now know that an adult mammalian cell can fire up all the dormant genetic instructions that shut down as it divides and specializes and ages, and thus can become a source of new life. You can outlaw technique; you cannot repeal biology.
Writing after Wilmut's successful cloning of the sheep, Dolly, that research on the cloning of human beings cannot be suppressed.