Dolly the sheep's heirs are in great shape: research

The heirs of Dolly the sheep are enjoying a healthy old age, proving cloned animals can live normal lives and offering reassurance to scientists hoping to use cloned cells in medicine.

Dolly, cloning's poster child, was born in Scotland in 1996. She died prematurely at 6 in 2003 after developing osteoarthritis and a lung infection, raising concerns that cloned animals may age more quickly than normal offspring.

Now researchers have allayed those fears by reporting that 13 cloned sheep, including four genomic copies of Dolly, are still in good shape at between 7 and 9 years of age, or the equivalent of 60 to 70 in human years.