The photograph of two baby monkeys clinging to each other crisscrossed the world early last year. Not just because the long-tailed macaques, Zhong Zhong and Hua Hua, were adorable, but because they were groundbreaking: They were the first primates ever to have been cloned. No scientist before had managed to make exact replicas of animals so close to us on the tree of life.
For some, the image was a bit too close for comfort. Long before Dolly the sheep was cloned almost 23 years ago, science fiction writers have fantasized about armies of look-alikes wiping out the rest of humanity, or clones bred solely to sustain their identical ancestors. The idea of clones is unsettling because it violates the fundamental moral understanding that we are all different and equally valuable.
Those involved with the science around cloning agree. Prominent scientists involved in cloning say they’ve never had any intention of replicating a person — and are as wary of the idea as everyone else. Their research serves other purposes, they say. For decades, investigations into cloning have been divided into two areas: reproductive cloning, mainly to improve livestock breeding; and therapeutic cloning aimed at growing cells, not whole humans, that could be used to treat diseases.
