The leader of Scotland's Roman Catholics said he shared the scepticism of many scientists over claims that the world's first cloned baby had been born.
The Archbishop of Glasgow Mario Conti, writing in the Sunday Herald, said he hoped the claims amounted to "no more than a publicity stunt."
But he suggested the only reason such "difficult questions" were now being faced was the fact that "several moral boundaries" had already been crossed.
He wrote: "One moral problem has succeeded another.
"The first step on this nightmarish journey was the British Government's acceptance of in vitro fertilisation, namely the production of human beings in a petri dish."
The Archbishop said this was followed by the go-ahead for experiments to be carried out on human embryos, including the removal of stem cells for research into disease treatments.
After this came a decision by Parliament, in December 2000, for scientists to be allowed to clone embryos up to 14 days old.
He added: "The attempted cloning of a human being is fraught with danger, both in its processes and in its results, with regard to the physical and psychological well-being of the cloned person."
Last month US-based company Clonaid announced that a cloned baby girl named Eve had been born to an American woman.
The results of DNA tests which could authenticate the claim have so far not been produced.