by Gunjan Sinha

About the author: Gunjan Sinha is an associate editor and columnist for Popular Science. He won the Ray Bruner Science Writing Award from the American Public Health Association in November 2000.

Forget Dolly. New cloning techniques produce cows with life-giving medicines in their milk.

Just beyond the greasy burger joints lining the main street of Worcester, Massachusetts, is a laboratory where a small group of scientists is tinkering with a technology that might forever transform the way medicines are made. The scientists at this lab are creating a new kind of drug factory, one without a single piece of machinery.

It will be made from skin, bones, and udder: a very ordinary framework for a genetically engineered cow that secretes medicine for humans in its milk.

Living Drug “Factories”

Steven Stice...