NPR's Melissa Block talks with Dr. Robert Lanza about the successful cloning of a pair of endangered bantengs, born a week ago. The banteng is a wild cow from Southeast Asia. Fewer than 8,000 are thought to exist. The pair of calves were cloned with DNA from a banteng which died 23 years ago at the San Diego Zoo. The experiment was a collaboration including Advanced cell Technology, the San Diego Zoo, Iowa State University and Trans Ova Genetic. Dr. Lanza is medical director and vice president of Advanced Cell Technology.