Making human-animal embryos for scientific experiments should be allowed because of the benefits to science and medicine, British experts said in a report released yesterday. Such embryos should never, however, be implanted into either a woman or an animal, said the Academy of Medical Sciences.

The combinations would include animal eggs and the nucleus, containing the genetic material, of a human being, or human embryos that carry the genetic material of an animal, the independent advisory body said. A cloning technique called somatic cell nuclear transfer involves removing the nucleus from an egg cell and replacing it with the nucleus of a cell from the animal to be cloned.

There are no laws against it in either Britain or the United states and the independent Academy said it should remain legal.

The powerful stem cells can give rise to any cell or tissue type in the human body and the hope is some day they may be used to tailor medical treatments for injuries or diseases such as Parkinson?s or diabetes.