In the milk of 30 genetically modified goats on GTC Biotherapeutics's farm in Charlton, Mass., is a drug that can literally make your blood flow--the human protein antithrombin, which inhibits clotting. In a dramatic reversal, after European reg-ulators rejected this drug (called ATryn), they now look ready to approve it later this year. The ruling would make ATryn the first human protein made by a transgenic animal for commercial production.

Perhaps more important, the judgment in favor of the goats paves the way for more drug-making transgenic farm animals. Origen Therapeutics in Burlingame, Calif., has developed a versatile, cost-effective method for genetically transforming chickens--one that is on par with creating transgenic mice, now common in the lab. In principle, the birds could produce a variety of different proteins in their eggs, including drugs.