The world's first cloning of a dog has raised concerns that scientists are one step closer to replicating human beings, despite the breakthrough pointing to treatments for currently-incurable human diseases.

The pet cloning industry, where pet owners can pay $35-50,000 to have their favorite pet cloned, is slowly maturing but critics charge that it is wasteful and inhumane.

Almost seven years after the birth of Dolly the sheep shocked scientists and the public, cloning has shown mixed progress. Scientists have achieved it in more than a dozen mammal species but an efficient cloning process still eludes them. Clones are more prone to physical defects than regular animals are. And researchers haven't been able to duplicate monkeys from adult or fetal tissue, a goal that could help medical research.

A design for creatures that are half man, half animal has raised fundamental questions about what it means to be human. Two critics of biotechnology want the U.S. Patent Office to answer them.

Researchers are investigating the use of cloned animals to help produce antidotes for biological warfare agents.

Warning that bioengineered animals could escape into the wild and muddy the gene pool, a new scientific report calls for more oversight of the entire field, including assessments of whether biotech meat or dairy products might cause allergies if eaten.

One of the key figures behind the creation of Dolly the sheep has backed the
cloning of animals for meat and milk. Professor Ian Wilmut, of the Roslin Institute near Edinburgh, claimed that the technique could overcome food shortages.