A new study on cloning shows more than ever it's probably a very bad idea to replicate human beings.
The study, performed by researchers at the Whitehead Institute for Biomedical Research in Boston, found that cloning to create new animals will almost always create an abnormal creature.
Rudolf Jaenisch and his colleagues report that the cloning process jeopardizes the integrity of an animal's entire genetic make-up in this week's issue of the Proceedings of the National Academy of Sciences.
The researchers looked at 10,000 genes, making it the largest study of its kind. A preliminary study of just 12 genes -- as well as circumstantial evidence such as Dolly the cloned sheep's arthritis and various clone stillbirths, early aging and other health problems -- had already suggested problems with cloning.