They Clone Cattle, Don't They?

Want to peek into a crystal ball and glimpse at the future of cloning? One way might be to look at the livestock industry, the proving ground for reproductive technology. More than a decade has passed since the first calves, lambs and piglets were cloned, and yet there are no dairy herds composed of carbon-copy cows, no pigpens filled with identical sows. While copying particular strains of valuable plants such as corn and canola has become an indispensable tool of modern agriculture, cloning farm animals, feasible as it may be, has never become widespread. Even simple embryo splitting, the technique used...